Firefox > Settings > Logins & passwords > Autofill in other apps.

Happy to discover this via another comment in this thread myself!

Why oh why this isn't clearer (or mentioned at all for Android) in the PR I have no idea. It makes a scary/annoying thing tame/nothing.

I suppose we missed the earlier 'deprecated, switch to this' memo?

It is my understanding that Firefox itself will work as general password manager for other apps.

Lockwise was far from the best -- probably closer to the bottom. So literally anything else would probably work just as well.

One of the best free (as in beer) password managers is Bitwarden.