that sounds wild! I cant think of a way they wouldve broken your 2fa...

Any way to make sure there is no compromise of your system in general? Is fb the only account that got taken over?

Your current steps seem very sensible to me. I recommend to safe your credentials in a safe store e.g. bitwarden.

If they have a fb exploit there is nothing you can do, but i think that would be a bigger story.