Samsung has the Google message app collaboration with Samsung , it looks like google icon app from outside but gives little bit of One UI feel with end to end encryption s21 and up come with this and im using the APK on my Note20U
Just so your aware of this .
Oh, so can you confirm that you get the encryption icon when chatting with someone using Google Messages? Also, what if it's someone using an older Samsung phone? I'm still hanging onto this possible explanation because it seems to jibe with what I see on my phone. On a couple of message threads with people who I know have Pixels, I see the encryption icon, but with another person who I'm pretty sure has a Samsung phone, I see the dark blue message backgrounds of RCS chat but no encryption icon.
Also, you say it looks like the Google icon from the outside -- but what about the Samsung Messages app? My A32 5G came with both.