Start with buying the right hardware. Fairphone offers more control over the hardware:
https://support.fairphone.com/hc/en-us/articles/104924762388...
I feel like such initiatives miss one obvious target - the well heeled tech savvy user (who quite often is also privacy minded) and wants the latest. At the price point they are selling a Snapdragon 7 device, I can get a Snapdragon 8 Elite phone from the market quite easily. Now I am happy to pay more because of what they stand for but I don't see them selling a model that features the latest and greatest + the privacy focus. Surely the latest hardware and privacy/environmental responsibility are not mutually exclusive. I change my phone every 4-5 years on average so I try to not contribute to the landfills but I do want the latest when I buy.
The OS they ship has Google services on it. They've previously chosen not to give you root access by default because Google wouldn't allow it: https://forum.fairphone.com/t/fairphone-s-approach-to-root-o...
They'll make the same choice again because it's not really a choice. Nobody would buy the device, or could make much use of it, without Google services on it. They'd be out of business
Edit, to be clear: that is not to say I disagree with what they do. They allow you to unlock the bootloader and they even supply an open and degoogled version of the OS! That is more than any other vendor I'm aware of. Every time I need a new phone, I check if the latest Fairphone fits my needs, and even though it's a compromise, I've tried it out in the past for several weeks. It's really worth supporting. But Google's new restriction will almost certainly affect Fairphone users, too