One whole year of terrible RCS messaging support. Don't know what to do.

AT&T Z Flip4 user here, really disappointed that AT&T still has not solved the issue of RCS messages not delivering to just about anyone not using a brand new AT&T Samsung phone (so nearly everybody). It's left me with undelivered messages all the time, spotty connections where it will automatically switch a SMS thread to an RCS thread even though it cannot connect. This does not happen on any phone I've used other than my AT&T phone. I don't want to get rid of my AT&T plan but with this kind of messaging support that has gone unresolved for close to a year since AT&T began using its proprietary RCS servers in Google Messages around the time of the S22 launch. I usually purchase my phones unlocked and move my SIM around instead of buying a phone from a carrier, and buying this phone through a carrier has proven to be the wrong choice. 

Makes me wonder how easy it would be to reinstall a clean copy of Android on my phone without all the proprietary, unchangeable software tweaks.