The long term practicality of this depends on mainline kernel support. LineageOS is cool, but the thing no one talks about is that while the Android stack might get updated, the kernel often isn't, which means any kernel level exploits remain unpatched after the support period ends.

Which is why this reads as kind of a stunt. A repairable phone is great, but if it becomes unsafe to use then what's the point? The software needs to be "repairable" too.