Too bad they have these long lists of "this doesn't work so well" and I'm too time constrained to troubleshoot for too long or dig for solutions. And I'd also need to replace the battery. It's an option for when I actually have some time.

The device integrity is a bigger deal, this is also a backup for some banking apps so if they don't work it kind of defeats the purpose. I removed all other apps to minimize the attacks surface.

If you're using it as backup for banking apps and the like I totally get not running a custom ROM on it! But you could also set that backup on something even cheaper, any one of the random not-bootloader-unlockable brands, and be left with the OP5 as a Linux phone. You're also right that the Linux support on OP5 is not up to standard yet, this is more of a question for the future if that support improves.