Worse, RCS isn't always E2EE. After Apple begrudgingly added it to iMessage, they've made sure that iPhones don't support its encryption, and I don't think they display reactions and such properly. Meaning a group chat with a single iPhone in it can't be encrypted.

That and the annoying dependence on carrier and proprietary software support - even with google messenger I've had RCS just give up sometimes and go to SMS only.

At this point, using an actual E2EE messaging system like Signal makes a lot more sense.