It’s about time. I hop between iOS and Android every so often, and the lack of RCS has always been a major pain in the ass. Goodbye shitty compressed photos and hello read receipts. Unless your Android vendor doesn’t fully support RCS… Looking at you, Samsung
If I understand your question, you can just assign some of your server endpoints a public IP/URL and keep some others behind the firewall. My home lab exposes some services to the open internet, while others are only accessible with a VPN.