In that case
the old method should still work. You can set
wallet.relayfee = (lambda: 0)
in the Qt console, and then the GUI lets you do whatever you want. Create even zero-fee txs.
This works. And it makes my entire project pointless....
All I wanted was an easy way to use Electrum to create a low-fee transaction, and my assumption was this is restricted by the server. But the code above indeed allows to create the transaction I want.
Question: what does the "lambda" part do?
Fulcrum is synced. 165 GB database.