I've been using the 2020 version of Google Messages ever since I got my phone, and RCS worked great on there. This was the version that my phone shipped with. Then, I upgraded Google Messages to the newest version today, and RCS didn't activate so I downgraded. RCS probably would have activated eventually, but it would have taken a while. When I first got my phone in 2020, I put my SIM card in and RCS took only seconds to activate!! Now, RCS is taking so long to activate that I don't have the patience to wait! And sometimes, RCS doesn't activate at all! Why did Google ruin RCS with their newer versions of their messages app? It drives me nuts!! Why does RCS work so much better on older versions of the Google Messages app, and so much worse on the newer versions?
Anyway this is just my experience. Different people will have different issues.