If you buy a new Pixel and then run an alt rom like graphene or lineage, you’re most likeley costing Google money. I believe they manufacture the Pixel at a small loss because they expect to make their money back harvesting and selling your personal data. Denying them that should mean you get decent hardware at a fair price, without really “supporting” Google as much as you fear. I could be wrong, but I’ve definitely seen that mentioned before.
+1 for pihole! Stupid easy for linux geeks to setup and maintain, but probably a pretty hard sell for the more general public. A cloud service like NextDNS might be more appropriate for average Joes. I can’t speak to AdGuard since I don’t use it, but I know that name gets mentioned frequently in privacy circles - favorably, I think…
Good choices. I too run Librewolf by default, with ungoogled Chromium standing by for the occassional asshat website intentionally designed to work exclusively on Chrome