You can click that "Accelerate" button and their prices per tier will appear.
And yes, it's significantly cheaper than ViaBTC's paid accelerator, even their maximum tier is less than half of viabtc's asking price.

The issue is, there's currently no user here in Bitcointalk that reported their experience with mempool.space's accelerator.
It would be great to have some legitimate feedbacks.

This belongs to "Service Discussion" board.

One indicator would be the block where it's included.
If the pool or solo miner uses a publicly known address that they own or put an OP_RETURN output where there's info about the miner,
then if that pool offers accelerator service, that may be a faint clue that it was accelerated.

In OP's case, the transaction was mined in F2Pool's block and F2Pool has their own accelerator service.

What we don't know is if mempool.space is working with them to implement their own accelerator service.
But I've created my own test account in mempool.space within the same timeframe as OP and it's still in "waiting list" as of now.

You mean this guide: [GUIDE] How to Safely Download and Verify Electrum [Guide]?
It's on the correct order but it has instructions for three different operating systems, one introductory introductions, then the complete procedure per OS.
So if you scroll-down too much without reading the headers, you might see another "step1" for another OS.

You can refer to the guide's clickable "Table of Contents" and only follow the instructions for your machine's operating system.

The guide is pointing to your GPG/PGP private key, it's basically the "secret" part of the keypair that you've created which consists of a private and public key.
It has no relation to Bitcoin's private key.
Since you now have a keypair, you can now proceed to import Electrum developers' public keys.

If the provided tutorials are overwhelming, try this simple one: bitcoinelectrum.com/how-to-verify-your-electrum-download/

Sorry, I didn't get the question.
If it's about the MultiSig wallet created from an existing standard wallet, then yes.

The addresses in the MultiSig wallet are completely different from the standard wallet and the keys used are derived from a different derivation path.
Now that I've mentioned it, it's worth noting to OP that he shouldn't use the master public key displayed in his standard wallets' info but the ones displayed during MultiSig wallet creation.
-edit-
As mentioned in the reply above. (hosseinimr93 beat me to it)

Yes, it's possible with standard wallet but not with 2FA wallet seed phrase.
The seed phrases created in Electrum MultiSig wallet are the same as the standard ones.

However, you cannot sign transactions using those standard Electrum wallets.
You need to create separate cosigner MultiSig wallets from those seed phrases and the other's master public key.

Yes, by design, your private keys are contained in your Ledger Nano S.
The created Electrum wallet with it only contains its "extended public key" which can only derive public keys to addresses.
Worst case, your privacy is at risk, not that using an SPV wallet like Eletrum is private in the first place.

However, an unverified fake Electrum app may trick you to send to a different address or anything that'll change the transaction's data before you sign it with your hardware wallet.
That's still dangerous if you do not pay attention during verification of the address and amount shown in your Ledger's screen.

So try to verify Electrum even if you find it hard to accomplish.
If you came across any errors, report it here so we can tell you what went wrong during the process.

Please provide a sample.
Of course, replace every character or word but keep the formatting correct like the number of characters and symbols.

Bitcoin Core doesn't and haven't supported "paper phrase" if you meant "mnemonic words".

My best guess is it may be a "Brainwallet" passphrase but do not do anything with it while online, unless you have access to an air-gap machine (wiki: Air gap).
In that case, you can try if it'll produce an address with balance using a working brainwallet tool (example) while completely offline.

No one can help you except them since they hold the private keys of their users' addresses.

As for their response, it seems like it's aligned with their TOS here: localbitcoins.com/terms_of_service
But there's no information about recovery of mistakenly sent funds.
The closest policy is about their altcoin recovery rule in "Acceptable Use Policy" which states that they aren't entitled to recover the funds: https://localbitcoins.com/acceptable_use_policy

The forum is very much active, it's just there's no known solution and there is nothing else to add to this thread.
Unfortunately, even the developers cannot help you with recovering the allegedly stolen bitcoins.

You already have a "convenient cold-storage" which is your Trezor, just use it instead of creating a hot wallet with less security.
The only hard part of using it is when plugging and signing transactions which IMO, isn't that inconvenient.

The alternative to that solution is to disable wallet encryption.

That way, the wallet can be opened without the plugging the hardware wallet, it'll only be required when the keys are needed.
There's no private keys in the wallet file so there's no major issue aside from privacy issue for when the unencrypted wallet file got in the hands of a hacker.
(the public servers if you're using those already know your addresses anyways)

It's not necessary bad, security-wise, because it's just the script verifications that are skipped.
Everything in the assumed valid blocks are still being verified by your node.

The topic is quite famous after its implementation so you will find a lot of helpful related topics across the internet.
For example: https://bitcoin.stackexchange.com/a/88666

Must be your RPi's CPU struggling on script verifications after v25.0's default "assumevalid" blocks which is before block height 784000.
Here's for reference: github.com/bitcoin/bitcoin/blob/v25.0/src/kernel/chainparams.cpp#L107C128-L107C128

It's not recommended but if you think it's necessary to speed up your node's IBD, you can set a custom assumevalid block by setting -assumevalid=<block_hash>.

Yes, those are the earlier versions before 0.21.0. (01-16-2021)
Here's the release notes: github.com/bitcoin/bitcoin/blob/master/doc/release-notes/release-notes-0.21.0.md

To get to the repository's state at that time, click your prefered version's tag above "Compare" button in the 'release' page: github.com/bitcoin/bitcoin/releases?page=2
Example for v 0.20.1: github.com/bitcoin/bitcoin/tree/v0.20.1

All you can do is to wait for them to enable your accelerator-service account.

After that, you'll have to deposit a minimum of 100,000satoshi.
Then paste your TXID on their blockexplorer  (use the "search" feature above their webpage)
In the transaction's 'ETA', click "Accelerate" and you'll be provided with various acceleration options. (the minimum should be enough in most cases)
Finalize it with the "Accelerate" button below.

Just for clarification, is your "Coinbase" the actual Exchange or "Coinbase Wallet" app?
Because you have a chance to CPFP it with the latter.

Contact the seller about it immediately if you're getting "bad-txns-inputs-missingorspent".
There are wallets that will instantaneously remove a transaction that's dropped from its mempool which could lead him to spend its input to another transaction unintentionally.
There also other scenarios that could lead to the same result like its parent transaction that got replaced via rbf.

Since you're the receiver, better maintain your communication with the sender who's in control of it.

Your 'debug.log' file may contain the files names and full path of the recently loaded wallet files
but since you've "shredded" it, there may not be any recoverable data from the drive depending on its effectiveness.
But in order to fully remove the trace, shred the logs as well.

The 'database' folder inside your 'wallets' directory could contain a log file that may contain traces of recently loaded wallets.
The 'settings.json' file may still contain its name if you just deleted the wallet file without unloading it first.
The "Open Wallet" drop-down menu in Bitcoin Core is based from the available wallets in the data directory, so previously used but deleted wallets wont appear there.
The cached data in your RAM wont be an issue after a few minutes.

Other than those, I don't know if there's any other traces of it. (wait for other users' inputs)

CPFP only increases the "effective fee" of the parent and children transactions, not necessarily increases the parent's fee rate.
You can only see that effective fee rate during creation of the CPFP transaction by hovering your mouse over " [→ CPFP " near the fee rate.

Anyways, AFAIK 0.00sat/vB in Sparrow is only possible if the fee rate source is set to "Server" and your selected server "Bitcoin Core" is configured to relay 0sat/vB txns.
If it's the case (not a typo), I'd suggest you to set to standard minimum because even though you're be able to relay such transactions, most of your peers and miners will just reject it.

That is the list maintained by LoyceV, link to profile: http://bitcointalk.org/index.php?action=profile;u=459836
The user is one of the most prominent members here in the forum with lots of good contributions.

As for the list's safety and data integrity, there's no way to verify, but refer to LoyceV's trust rating which is in very high positive standing.

It's quite okay here in the 'Beginners and Help' board since mods aren't too strict to newbies in regards with being off-topic.
But if the provided solution didn't work, I suggest you to open your own topic because the issue may be more than just an unsigned transaction which could require a few more info.

If it requires a new topic, read this topic first (link: Tech Support Help Request Format) and post it in Electrum (link) board.