Buying used still inflates the price, giving Google more money. Plus, Google is now sending you firmware updates. I like Fairphone, and there are a few ROMs you can flash onto it. But unfortunately not grapheneOS. Maybe LineageOS (without MicroG) would be the least googly, but there would still be some Google bits and bobs you’d have to turn off. /e/OS is probably a bit more degoogled, except for MicroG, which is kind of a big exception. No android is completely degoogled, it seems. There is a promising Linux phone coming to Europe soon though, the Jolla phone, and I’m hoping it gets good reviews and then comes to the US.