I have only used Android phones and I strongly dislike RCS. RCS in theory is a standard but in practice it is == "Google Messages" the app. I don't know of a si

I have only used Android phones and I strongly dislike RCS. RCS in theory is a standard but in practice it is == "Google Messages" the app. I don't know of a single telco that supports it (hosting their own infra of it), nor does any other SMS app (maybe 1 or 2 being exception that proves the rule). RCS(Google Messages) is just another messaging app like Whatsapp/Signal just that it pretends being a standard. AFAIK AOSP has no RCS APIs like it has for SMS. Not to mention the amount of SPAM one gets on RCS is comparable only to traditional SMS, and blocking has no effect unlike Whatsapp. It exists mainly because Google got tired of making messaging apps that weren't dominating the world (Hangouts/Allo) and thought that forcing a standard might be the only option available to them. E2E is optional and there is no switch that says only do E2E. There might be some solution needed to let iMessage interoperate with Android, but pretending RCS is a standard just like SMS that Apple was not supporting is wishful thinking.