IIRC Bitcoin Core has an option to forget the transactions without having to mess with databases or jsons. -zapwallet I think.
There are some miners that run mempoolfullrbf nodes. And they should , greedy people wanting higher fees. I was thus able to save a stuck transaction that was hanging for weeks - with fee just above the purge limit, but too low to get mined.
Glory to the greedy miners who ignore the nonsensical flags. Now let's completely abandon rbf flagging and make it default.
(if you are asking why I did not do CPFP - it was a full sweep to a swap contract address, no other way to bump it).
How did I do it?
1. Find the stuck tx id
2. Import seed to Electrum
3. Quit Electrum, turn off wifi (so Electrum does not get the transaction back from mempool when it is started)
4. Manually remove all mentions of the txid in electrum's wallet file - make sure you don't break the json syntax
5. Start electrum, spend the coins
6. Don't broadcast, copy tx hash
7. Turn on wifi and broadcast the tx using the hex using http://blockstream.info or mempoolspace tx broadcaster
Next step - electrum should make this a one click operation, as if it was rbf tx in the first place.