Update I have come to a decision. Thank you to all who contributed suggestions. Please feel free to keep the discussion going to help others.
Whatever idea you have to phones, you‘re wrong. They can easily make 5 plus years if you treat them right. The more problematic part is daily use and battery degradation/repair.
But google sucks anyway so I‘ll stay with postmarketOS on my oneplus6 and wait for my camera to come to life some day (hopefully).
Interesting. I have a vastly divergent opinion on linux for mobile, mostly that it is not secure. This is true for Desktop linux but is more important considering the threat model necessary for mobile device Security.