RCS sucks. I don't want to be beholden to Apple or Google. I don't even use a Google account on my android phone so RCS doesn't work. And that's fine. RCS was originally built to make the telcos have a finger in the SMS pie again, but they lost interest and it was embrace extended by Google. Their end to end crypto additions are not part of the open standard.
People can reach me on signal or on WhatsApp or Telegram. RCS (or SMS for that matter) will just go ignored.
If RCS were truly open and I could run my own server including E2EE and iMessage connectivity etc it would be another thing.
Right now I have matrix which bridges my chats to all the other networks.