Pull request already submitted - it’s not in BitWarden code, it’s in a dependency.
Afterwards the mobile client(s) need to be changed to use the new version of the dependency, if the pull request is accepted.
I’ve also raised an issue before doing the pull request which has a bit more information.
Unfortunately it seems like the device manufacturer can decide which biometric authentication is STRONG and which is WEAK, but from what I can tell usually manufacturers consider face as WEAK (Samsung for sure).
And others on the internet also mention that face unlock is weak.
Maybe someone with more Xamarin and Visual Studio knowledge could help with the pull request, I had problems updating the MonoAndroid version. Once the Xamarin-Plugin is updated I would assume BitWarden can use it in the next release and allow people to choose which method to use for unlocking … or better yet, always request the STRONG type, I don’t know who would have a problem with that considering what BitWarden is used for and who usually uses it