In Bitcoin core whether it's RPC or the GUI, the change will be sent to a "change address" derived from a different hdkeypath m/0'/1'/.
And those wont be used as "receiving" addresses nor return in getnewaddress command.

In addition to HCP's reply, just like "receiving address", Bitcoin core has a reserve keypool for the change addresses that consist of 1000 key pairs.
So there's a total of 2000 reserved keys.

The other one with 66 characters is the public key, in compressed format. It should start with either '2' or '3'.

According to this: https://bitcoin.stackexchange.com/a/96070,
Broadcast is related to the node's "Min Transaction Relay Fee" setting, but will increase if the node's mempool size reached maximum.

Perhaps their min relay fee is actually higher at that time and your transaction wasn't really relayed/broadcast, you can try to re-broadcast it now and check the 'I' icon "Confidence" rating to see how many nodes have accepted your txn.
They will even accept 0.5 sat/vB txn but you'll notice that it's dropped after a while, try it  

But the error message that you're getting from blockchain(com) if your 'native SegWit' txn has 1-2sat/vB fee is still because of their erroneous computation of the fee rate whether their mempool's size it at max or not; if higher, it's the combination of both.

AFAIK, Blockcypher accepts non-standard transactions, that includes txns below their min relay fee and other 'issues' but will fail to relay them to most nodes, usually, they will drop it after a day or a few hours.
(just saved in their blockexplorer database, not relayed perhaps?)

I guess not.
Honestly I haven't reviewed that online wallet, but upon fiddling with the clickable options, I've found this: https://status.coinb.in/
Their Min Transaction Relay Fee is currently set to 10sat/vB, so the error in coinb.in is for a different reason, the "other 2" however may still be the "sat/B vs sat/vB" case.

I guess your transaction is SegWit and the fee rate is about 1-2sat/vB right?
Those services (like blockchain.com) computes the raw size of your transaction making the total fee rate in sat/B less than 1sat/B (not virtual Bytes), so they return with that error.

You can paste the TXID of the already broadcast transaction in the explorer of those sites that rejected it and you'll the that your fee rate is lower than minimum standard (only to them).

So it's the lack of confirmations when you last checked then  

You mean "pending" in Bitcoin Wallet app? Check ranochigo's reply above for possible network sync issues.

You just have to remember these:

• If it's an "Imported" wallet, you can add more keys (for Imported) or addresses (for Imported watch-only) in the already-created wallet using the options explained above.
• If it' an HD wallet like "Standard", "2FA" or "Multisig", you can't add more keys/address aside from deriving your keys beyond the gap limit.

The transaction's output was already spent and it looks like a deposit to a centralized service for having too many inputs in the transaction that spent it.
Most of those service only credits the user's funds once the transaction has 6 confirmations, some less.
Yours have more than enough now. Have you checked your balance recently?

-posted before I notice the reply above, but still relevant-

Even so, there're some inconsistencies because if there's some something wrong with the passphrase and there's no quotation mark, the result should be the 'help' for walletpassphrase.
Instead, he said it's "method not found (code-32601)".
So I guess if it's the keyboard's fault, he may have used "Pin Yin" when typing the walletpassphrase command at the time when he posted the OP.

Then somehow solved that first issue by using a different keyboard format, copy pasting the command or other.

Hmm, that's odd.
If that was the issue, you shouldn't be getting the "method not found (code-32601)" error; instead, it should be returning 'help' for walletpassphrase command if there's a 'space' in your password or a 'blank error message' / 'invalid command line' if there's an invalid character when you didn't add the quotation marks.

Anyways, good that it's now solved at the end although there are inconsistencies in this thread.

The most noticeable one is the GUI, there will be no wallet UI, just the 'Console', 'Information', 'Peer' and 'Network traffic' tabs.

To re-enable the wallet (if disablewallet is the culprit):
Check your Bitcoin data directory (location) if there's a "bitcoin.conf" file inside it, if there is, open it using a text editor and check if there's a disablewallet=1 line.
For a possible added start parameter, if you're on Windows and running using a shortcut, check its properties and look for -disablewallet at the end of the Target, if there is, remove it.

Those commands will work whether your node is synchronized, disconnected or not.

Based from the hint above, do you somehow have a disablewallet=1 entry in your bitcoin.conf file or as an additional start parameter in your shortcut?
Because disabling the wallet will make 'wallet RPC commands' like walletpassphrase disabled.

Whenever you see that "prompt" 'method not found', it's most likely that you've typed an incorrect command.
Check for typo in walletpassphrase then use the format posted in the above post.

have you imported the private key(s) of the input(s) of the transaction that you want to replace in this thread: /index.php?topic=5313492.msg56235634?
If so, you can easily send it back to yourself using "Cancel transaction" or perform RBF using "Increase fee" right-click options in the history tab.
The total fee however can't be edited using those options, the best you can do is to set the 'fee slider' to "static".

Maybe you've followed an old tutorial about fee bumping using abandon transaction back when there's no "Increase transaction fee" option like this one for Bitcoin Core v0.13.2.
Because what you're trying to do is basically what that option is, and its the "simple method".

Info: Abandoning the transaction wont delete it from other node's mempool so if you've sent another transaction to the same recipient but didn't used any of the inputs of the txn that you want to replace, then it won't be replaced, it's like you've sent to that address twice.

Anyways, if you decided to use "Increase transaction fee" and you want to set the new fee rate manually, you can use the console instead.
Use the command bumpfee and add the option fee_rate to set the new fee rate in BTC/kvB.
Example:

Your transaction maybe not yet broadcast or had errors.

I forgot to mention, if ever those 2 missing transactions didn't show up after a few days, you can do a rescan command.
In the console, use rescanblockchain and Bitcoin core will rescan for your wallet transactions (it'll be slow but it wont download anything unless your node is pruned)

Also, your new transaction must have at least one input from your "low-fee transaction" or it wont replace it.
That's why I've suggested to use coin-control.

You're in the right timing since the current average fee is quite low, try any recommended fee that's not under 10sat/vB and not higher than your target confirmation time.

BTW, you could have used right-click option: "Increase transaction fee" in the transactions tab  

Since you've used zapwallettxes, all of your wallet's transactions were removed and Bitcoin core is currently looking for them from your local copy of the blockchain.
Don't worry, those will be back after a few hours.

You can send it to any address that you want as long as the fee is higher than the previous transaction, at least an additional 1sat/vB would suffice.
You may also need to use "coin control" to select the same input(s) if there are other unspent transaction outputs in your wallet.
To enable it, tick "Settings->Options->Wallet tab->Enable coin control feature", that will enable the "Inputs" option in the send tab.

Your wallet may have been rescanning for those "zapped" transactions, and it's quite resource heavy.

May I ask your goal by using zapwallettxes?

Is the original query still up?
In Bitcoin Core, adding walletbroadcast=0 to your bitcoin.conf file will enable you to create wallet transactions without sending it to your own mempool.

If you use the GUI, simply create a transaction using the send tab but when you click "send", it wont be sent to the network or even your mempool (the transaction will have a Status: 0/unconfirmed, not in memory pool).
Then you can use "Right-click->Copy raw transaction" on the particular transaction to get its signed RAW transaction.

In Bitcoin-cli, sendto will simply create a transaction but wont send it to your mempool; but since it's in the wallet, you can use gettransaction to get its signed raw transaction.

Have you "frozen" any address or coin in their particular tabs?
Frozen addresses and coins will be highlighted with blue, coin's highlight will be under 'output point'. Check those tabs if there're blue highlights.

If so, you should right-click on an address/coin and select "Unfreeze address" or "Unfreeze coin" depending on what's frozen.