Heads up: Users are reporting that the Google Messages app won't let them send or receive RCS messages if the OS is rooted or hasn't passed GMS certification (like most custom ROMs).

It seems that Google Messages has implemented Play Integrity API attestation checks, so be aware if you root your device or install a custom ROM, you may lose access to RCS in Google Messages.

More discussion here: https://www.reddit.com/r/androidroot/comments/1b36hij/psa_google_is_quietly_blocking_rcs_on_rooted/