How well is autofill in an iOS app supported?

I have been trying to enable autofill in iOS apps by obtaining the app bundle ID and adding that as an alternate URL in my Bitwarden vault. The procedure for obtaining the bundleId of an app includes searching for the app in Apple’s app store and then using another URL to download a file and search for the bundleId in that file. That part is easy and I have no questions about that.

What I have found is that autofill in apps does not seem to be widely supported by the apps. I have configured bundleIds as alternate URLs for 8 different iOS apps. Out of those 8, only 2 autofill the user credentials from Bitwarden. Is this typical? I’m just curious if others experience such a low rate of support for this. I understand that it is up to the app developer to support this functionality and not Bitwarden.