So in the new upcoming major feature update for IOS, Apple is adding RCS support in there messaging app. What are the privacy implications of adopting RCS?

Is there any other apps that have RCS support on Android other than Google’s own messaging app?

The reason for my asking is because I was considering migrating my relatives’ messaging app to a RCS supported one because they will probably most likely enjoy the extra bandwidth of RCS.

Note, they’re already using Signal, Telegram, and WhatsApp for most of their conversations.