Unless you also convince the rest of the world to do the same, it's not gonna work.
It's gonna be like with mobile apps, where sure you can root your phone, or use a degoogled android rom, but then your bank will refuse to let you use their app (right now one can still use their website, but if this passes...), and a bunch of other things won't work by design.
Me boycotting my bank's app, or other root-averse apps, or non-google-android-rom averse apps, never stopped them from continuing to do what they do.
How do I de google my android? I didn't know that was a think, I thought my only option was graphene which doesn't work for my hardware or maybe Ubuntu touch which is unoptimized
Also waste their time by sending feedback that you're boycotting them and why. That's more money they'll lose having to read and respond to emails etc. If you get a bot response just keep casually replying to the email until a person responds.