I haven’t :) I think for most users the free version is everything they need. For $1 or $3 (depending on the tier) you get the ability to store and encrypt files instead of just passwords and text notes, etc. More on that here: https://bitwarden.com/pricing/
Of course they can be disabled. But sites are not all built the same way, so there isn’t one silver bullet we can tell you about to disable them everywhere. On mobile it’s even more difficult because access to browser plugins is more limited, along with developer features within the browser.
I also use FF on Android, and until recently was also using Reddit. There isn’t a good way to remove that bar.