I am not sure why this problem hasn't been solved for so many people... 

This may have been solved elsewhere, but I just fixed it. We had updated to 2021 and all of a sudden our bank feed wouldn't automatically create rules and all of the ones we had were LOST. Here are the steps to fix it (this is for 2021 and above desktop).

Edit > Preferences > Checking > Company preferences

Go to bank feeds, and change from Advanced mode to Express  mode.

BOOM - all our rules are back. I figured this out browsing the web on my own and trying things. I called QB support, got the run around constantly, and have probably spent 10 plus hours on the phone to resolve this. Numerous escalations and ZERO help from them.

Hopefully this works.