I think I’ll want the PinePhone Pro because repairability is important and it’ll probably be hard to find parts for outdated mass market phones. The original PinePhone is just too slow for me (from videos, not hands-on usage), and the PinePhone Pro probably wouldn’t be a huge downgrade from my current phone in terms of performance.
I didn’t see a big selection of used OnePlus 6s (OnePlus 6T seems available though), and the ones that are available are in poor shape (shattered back, burned in screen, some kind of damage, etc), so it’s not going to be a long term option most likely. The PinePhone should have decent parts support for a few years at least.