Documented hardware and mainline kernel or is it like every unownable other phone with an orphan kernel to steal ownership from the consumer? Orphaned kernels mean rental phone you can never own. This is the depreciation mechanism in Android. This is the only question that really matters in the big picture grand scheme.
If it has a mainline kernel, and hardware documentation, it will last decades even as a spare backup you never actually use. It will run any Linux, or find a second life in dozens of ways. It will even have long term value.