Bitwarden still doesn't support it on mobile, where it would probably the most useful, partially because Bitwardens auto fill on android is extremely unreliable, especially when dealing with two login pages (email then password).
Bitwarden doesn't have support in apps, but you can get passkey support in Firefox by installing the Bitwarden addon.
I would've preferred more integration here (because unlocking the app vault doesn't unlock the addon vault, for example) but I think this is just because of the lack of proper APIs for this kind of thing. Android's auto fill API is using the standard system API, but the system API clearly isn't designed for the "enter your username, hit next, then enter your password" flow.
