ICC is new and required for some carriers, the rest has been like that for a while
https://grapheneos.org/usage#rcs
I choose RCS not just for the features but because up to 1 company probably obtains my texts rather than me sending plain text, not encrypted, messages and pics to my pals. At the very least your carrier reads the message, possibly other MITM or the government.
Whatever you're more comfortable with.