I've lived Google-free on my Android device from day one with CM/LOS (4 years). Unless you're specifically tied to some proprietary piece of software (e.g. faceboon, slack, etc.) it's not really a problem. I managed to convince 12 people to use XMPP, the rest have to call me/send sms/send email.

Actually, my current setup is more open source than sailfishos