I was able to get RCS working again yesterday by updating to the latest version of Play Integrity Fix, but if that hadn't worked, I would have disabled it and then probably switched over to Textra or Yatta for texting since RCS is basically the only thing keeping me on messages for texting.
I've disabled it for now. Rooted phone is enormously more valuable to me than RCS that only half works right to begin with.
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