I usually look for a phone that has proper LineageOS support and a strong xda community of third party ROMs, Kernels and what not.

I usually go to LineageOS's download page, and browse through the phone list for a not so old phone that has builds for the newest version. Afterwards I check its xda page, read the specs for the phone, check reviews on YouTube and finally decide.

I used to like Pixel phones, but sometimes even the Google experience is too much for me.

These things are a matter of personal preference, take the community's opinions then decide on your own based on your use cases.