RCS doesn't inherently depend on Google servers. However Google doesn't see eye-to-eye with anyone. The carriers want their own version of RCS and Apple doesn't want to deal with it. Of course it's easier to get clicks by bashing Apple than by holding the carriers accountable (or supporting your own deprecated messaging platforms).

https://pocketnow.com/why-you-should-probably-avoid-googles-...

Google has exactly zero credibility here. Look how many messaging platforms they've created and killed off. Who's to say Google won't kill off RCS when they get a chance?

https://killedbygoogle.com/