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.

He doesn't have the 12-word recovery phrase, all he mentioned in the OP is a 8-12 possible characters of the password.

Plus he posted this:

No one can really help you if it's in Coinbase, not even their customer support because of the address' script type incompatibility between 'Bitcoin Cash' and the 'Bitcoin'.
I had asked in your previous thread of what "Coinbase" your coins were sent to.

Alternatively, the first characters of the address where it was sent should give the info if it's recoverable or not.
Does it start with '3' or '1', 'bc1' is out of the question since BCH can't be sent to it?

You didn't replied to your previous thread. If you can't find it, Mods moved it to 'Exchanges' board (link).
Because if it's 'Coinbase', not 'Coinbase Wallet', there's no point in reproducing the issue.

These are the wallets' links:

• Coinbase Wallet: https://play.google.com/store/apps/details?id=org.toshi
• Coinbase: https://play.google.com/store/apps/details?id=com.coinbase.android&hl=en&gl=US

Which one?

If you decided to do that, you should increase the database cache of Bitcoin core in your iMac to about 6GB to further increase the sync speed.
The option is in "Settings->Options->Size of database cache" just below 'prune', setting it to 5722 should provide significant sync speed boost.
You need to restart Core for the changes to take effect.

Yes, only your own (the built-in wallet) transactions. The node's functions like transaction relay wont be affected by walletbroadcast=0

If you're using the GUI, Bitcoin-qt, you can view those outbound peers in "Window->Peers", select an outbound peer and look at the right pane.
You'll notice that both "Sent" and "Received" are both actively updated, so it's as said above.

The configuration/bitcoin.conf entry that falls under your concern is blocksonly (info).

It the connection icon didn't even change, you might have improperly selected a server.
The right way is to right-click on your selected server then select "Use as server" from the right-click menu.

What particular Coinbase app? "Coinbase Wallet" or "Coinbase"?
Because the latter is a custodial wallet plus exchange and the former is a non-custodial wallet.

If Coinbase, then do the instructions above about contacting their support.

If it's Coinbase Wallet, you can restore by importing your Recovery Phrase to Electron Cash (https://electroncash.org/) or other clients that supports BIP39.
That's the 12-words that you need to take note during wallet creation;
for Electron, use the options, "Standard->I already have a seed->paste it->change the derivation path into m/44'/0'/0'  "
Finish creating the wallet, wait for the block headers download in the background and the wallet's balance will be updated.

I dunno, bitcoin.conf is empty by default so you might have set it unintentionally.
Also, depending on your use-case, you might not be needing the other entries that you've added to the config file.

BTW, aside from deletion, commenting the line will disable it just like what you did in rpcuser and rpcpassword.