As for the 3XL v 4XL, the latter has FaceID instead of fingperprint (which AFAIK isn't supported by any UK banks yet)
Very true, I'm hammering the banks via app reviews and support and pointing out that they are using a deprecated API for authentication when they should be using the new biometric one introduced in Android 10. The FaceID thingy works extremely well if you use a password manager. Any website or app where it asks you to log in, the password manager pops up, you're already looking at the phone so boom it autocompletes and logs you in. It works even better when the credentials are spread out on separate pages as the password manager captures this. No more multiple fingerprint tapping.
At this point I think I'm prepared to say that if you're not using a password manager (just pick the one that suits you as long as it supports biometrics) then you're missing out when it comes to the P4/P4XL. The FaceID makes it brilliant.