1: I uninstalled google messages then reinstalled.
2: opened Samsung messages and reset that as a default.
3: then opened google messages again and set it as my default.
4: waited an hour and now it's working and finally the chat features is staying on connected.
What a chore!
I have a similar issue. The difference is that the Google messages app doesn't even try to reconnect rather it states that the chat features are not available for this device.
This only happens when I switch to the Samsung messages app, set it as the default, return to the Google messages app and set it back to the default.
The only solution I've found is to open system settings, apps, scroll down to the Samsung messages app, open it and select storage. Clear the cache files and restart the device.
This works great every time. Google Messages chat feature connects and stays connected
Messages apps never seem to play well together. Still can't rule out the recent system update these days.
Just cuz we're talking about messaging, Samsung Messages is working fine with RCS Chat on VZW.
Galaxy S21 Ultra 512g(VZW), Galaxy Book (original, VZW), Tab S4, Galaxy Watch3 (VZW)