While it's true that Google is it's loudest and strongest proponent, RCS is actually an open standard "owned" by the GSMA, which is a European-headquartered and dominated organisation. It's entirely possible to completely implement interoperable RCS end-to-end without ever touching any Google software or services.
Completely different to WhatsApp where the entire stack is entirely proprietary and closed. It's very naive to put all your eggs in one basket for a service that has become so important to society as messaging. Even if the company running it seems benign. But I do wonder if Europe would be so complacent if Meta were, say, a Chinese company?