Device lend refactor (this time with more commits)

!33 (comment 30006)

I tried my best, I didn't really do that refactor in "a series of small easily retracable steps" - That's not really how I tend to code, I moreso rip apart medium sized chunks, put them back together, then compare to the original code & test every case in practice on both branches

So it was a bit hard to split it up into individual commits, but I think I did a decent job of making it followable?