Yes, 'Submarine Swap' should do the trick, so the actual issue is your channel's connectivity.
The "No path found" error happens if your channel cannot find a route to Boltz's channel to pay the to-be-swapped lightning funds.
Connecting to a well-connected node with many channels may help.
Also, if you're not using "trampoline routing", it may take a while to fully sync with the lightning network. (seen as the percentage in the lightning icon)

You can also try directly swapping through Boltz website and see if there's a difference: boltz.exchange
It's the same service as Electrum's swap feature.

That version supports descriptor wallets despite not creating such wallet by default.

Then, the mirrored wallet isn't "descriptor" with watching-only descriptors, it's the legacy version.
Because the "Send" button should've been replaced with "Create Unsigned" if it is.

The alternative for non-descriptor wallet is what o_e_l_e_o pointed out but you need to update your Bitcoin Core for it to appear in the "Confirm send coin" window.

Once it successfully synced, yes.
My reply above this quote is just an option in case Electrum didn't sync.

As additional note, if the watching-only wallet isn't a "descriptor" wallet, you won't be able to use that option either.

If you want to spend them through that watching-only wallet, you can try this:

In Bitcoin Core, there should be a "Create Unsigned" option in 'Send' tab to create an 'unsigned RAW transaction'.
Create a transaction with appropriate amount of inputs and fee, then save the ".psbt" file in a flash drive.
(your txn will be high in size so don't set the fee rate too high)

Open your 2FA Electrum in an offline machine (restore it from seed to be able to use it offline).
Load the .psbt file through the menu "Tools->Load transaction->From file", you should be able to sign it using two keys (Review the outputs and amounts).
After signing, export it through "Export->Copy to Clipboard" and find a way to transfer the copied Signed RAW Transaction to your Bitcoin Core.

Lastly, in Bitcoin Core, open the console (Window->Console),
In the Console, enter the command: sendrawtransaction "PASTE_THE_SIGNED_RAW_TRANSACTION" to send the transaction to the network.

Note: tested only on single-sig SegWit, haven't tested if the watching-only wallet created for EPS includes the redeem script; depending on the watching-only copy, this method may not work.

The list in the 'Receive' tab is just for invoices, it's not remotely important when it comes with the balance so don't mind it that much.
The reason it's removed from the "receive queue" is because the address now received bitcoins and the invoice was fulfilled.

Since it's in your addresses tab, then it's not a clipboard malware but something to do with your PC's security.
Having fake Electrum isn't deducted to the possible cause either until you verified that the signature matches.

I'm afraid only be finding the culprit to "convince" him to return the funds.
Due to Bitcoin's nature, there' no way to reverse an already confirmed transaction, by checking the address in question, all of its txns are already confirmed.

What do you mean "gone"? It's not in the 'Addresses' tab?
If you don't have Addresses tab activated, click "View->Show Addresses" to toggle the tab.

Because if it's not there and there's a similar address in the list (or even not), chances that you've been a victim of "Clipboard Hijacking Malware" is high.
You can Google search the term for more info.

Well, Kraken can't be blamed here since they don't have access to your wallet's private keys.
After you've sent it to your Electrum, only the private key of the address where it was sent to can spend it, in this case, your Electrum wallet.
The possible causes are: compromised PC, leaked private key or seed phrase.

Based from available information at the moment, it seems like you're not the only one who's got robbed.
But it's not possible to tell how without knowing the PC's condition (how it's used) and how the wallet is created.

Have you updated Electrum lately? Say, a message when you tried to send a transaction?
If so, what was your Electrum version prior to the update?

That's because most versions from 2018 are vulnerable to phishing malicious messages from rogue public servers.

Also, verifying its signature will clear all doubt about it being fake, guide: https://bitcoinelectrum.com/how-to-verify-your-electrum-download/
You can download the signatures for old version in "Previous Releases" link in Electrum download page.

Kraken can't control the funds sent to your Electrum; also, being hacked isn't the only way to compromise your Electrum.
For example, your seed phrase.
So, have you stored your seed phrase somewhere vulnerable?

The transaction going to 1DRJ3pkdSXTgYh59Rv7yUUQBErhTJ5rskB has a transaction fee.
Electrum just won't display it in the history tab, you'll have to open the transaction's details.

They are talking about the Bitcoin "blockchain", and not "Blockchain online wallet" of blockchain(dot)com.
That's the huge set of files that most Bitcoin node have in their drive, it consist of "chain of blocks" where the transactions are recorded.

Electrum and any other Bitcoin wallets don't contain bitcoins, they only manage the coins accessible by the "private keys" stored in them.
And as an answer to your question, all of your wallet's "private keys" can be derived from your seed phrase so be sure to keep it safe.

Any chance that the wallet is created by later versions of Bitcoin Core?
Because if so, pywallet doesn't support "descriptor" wallet.dat which is the new default.

Version is '1.1'
The number '22' belongs to the error message.

Not just the site, the lawyer is also a fake.
Electrum and Bitcoin don't work like a bank, stolen funds can't be recovered by an authority nor the developers of Electrum or even Bitcoin Core.
If you're scammed, chances that it's the same scammer who's trying to get more out of you.

That tool is designed for claiming Electrum forks from non-SegWit 2fa electrum
and since those forks don't support SegWit, there's no reason for Trusted Coin to upgrade the tool to support 2fa-segwit Electrum seed.
(or they do not have the time to update it)

Also, it's basically the same as restoring your 2fa seed phrase to Electrum except the restored wallet file is in "skeleton" state
which only consist of necessary data to be compatible with all Electrum versions and fork.

Then it should be able to see the unconfirmed transaction.
Right-click on "Unconfirmed" and select "Increase fee (CPFP)" and proceed to create a transaction that'll bump its fee rate.
Sparrow has the capability to CPFP your outbound transactions if it has enough change.

It's what LoyceV suggested in the post above.

Yes, most Hardware wallets are basically the same as software wallets when it comes with derivation path since it follows BIP39 standard.
Although I don't know what you'll do with the master fingerprint showed in Sparrow since it's not too important when it comes with derivation of the child extended keys.

LoyceV's "Pretty Addy Giveaway" thread has detailed instructions of an example of split key method.
The tool used in the instruction is bitaddress.
Link: https://bitcointalk.org/index.php?topic=1813624.0

Alternatively, you can do that solely in VanitySearch if you prefer that tool through -kp, -sp and then -rp commands.
However, it doesn't have a secure way to generate the initial keypair (it requires a passphrase which works like a brainwallet).

I've created a test Sparrow wallet to check this and it's indeed talking about the fingerprint of the master private key but it's used for "Descriptors".

Here's some info on my test:

• Sparrow wallet's fingerprint: 4807233c
• Master private key derived from the seed: tprv8ZgxMBicQKsPe8tmAeXPxny3zpm5dWPHCCu6ffhHJc4FAeT2NrToDsi6jfMc7RLBmALgxmcwt5x Ti1nFGwsqYNam66kH6KMo8tt8edpJmAC
• ECDSA Private keys extracted from the master private key: 66c5c77c1e6f08a95c5d7c710d69533e2a7c576abff45596e4a27a02e9437778
• Compressed public key pair of the above: 03f1daf4af89d74e1ce1ee316611f07eba7e514ded038239d0606aeb813f6ff854
• SHA256 of the above: fdeb7f8fc5a4183fe66ccc776fead2b6672248cbe678cc60b533c24f9b298537
• RIPEMD160 of the above: 4807233c55a0065205e18a30871b5b3ee9a101bc
• First four bytes of the above: 4807233c (same as the "master fingerprint")

Yes, if you're talking about Sparrow wallet's master fingerprint
It won't change since it's solely derived from the 'public key' pair of the 'private key' part of 'master private key'.

It should be hashed from its parent's public key and not the whole xpub either.

I don't know what you meant by "master fingerprint", perhaps the fingerprint of the master private key?
If so, the master private key which doesn't have a parent has its 'fingerprint', 'Depth' and 'Child Number' all set to 0x00 (with the correct byte size).

Okay, IanColeman's BIP39 tool indeed can't do it.
Your option in that tool is to start from the 'BIP32 Root Key' using your master private key in an offline environment instead.

My concern is if Casa is using its own derivation path, it could complicate things.
I'm not using their service so I may not be able to help you with it.

You can multi-select them all by utilizing SHIFT or CTRL and then right-click to select "Spend from".
The total will be displayed below in the "Coin control" bar highlighted in green.
Tip: In the 'Addresses' tab, click the "Balance" row to easily sort out the addresses with balance.

Click "Reset" after taking note of your balance.

If there's a mismatch and you don't have any channels open, I'd suggest you to report this to Electrum's GutHub repository: https://github.com/spesmilo/electrum/issues

The question is quite hard to interpret.

What do you mean by "public key changes"?
Because IanColeman's BIP39 tool has "Account Extended Public Key" and "BIP32 Extended Public Key" that changes if you change the associated derivation path.

If you mean the "BIP32 Root Key", it's unnecessary to have a public pair since it's "hardened" in which you can't derive the child key from the master public key.
If you mean the addresses, you can toggle the public keys by clicking "TOGGLE" next to the "Public Key" column.