Earlier quoted context omitted.
AFAIK one of the best solutions for smartphone privacy is using a custom Android ROM without Google apps installed. Of course that means basically no 3rd party apps, but you can still get a surprising amount of functionality with just a web browser. You’ll still get tracked by your mobile provider, but I think that would happen even with a dumbphone.
You can use microg. It's a Free reimplementation of google play framework, so that apps which depend on it can still function in a de-googled phone. It's imperfect, I admit it, and breaks some apps, but it's still a massive help.
TL;DR: no Google, most things work, but not necessarily smoothly. I've used it for a few years now.
[1] https://lineage.microg.org/ [2] https://f-droid.org/en/packages/com.github.yeriomin.yalpstor... [3] https://puri.sm/products/librem-5/