One commonly suggested way to still get a secure device such as a modern Pixel without supporting the big tech companies is to buy one second hand. That way your money goes to whoever is reselling the device instead.
I really can’t recommend you get a Fairphone. While I understand the appeal of such a repairable device they are chronically insecure due to slow updates, and historically using AVB test keys, among other shortcomings. See more here: Fairphone 5.