I don’t work in tech but I’d spend my own dime in a heartbeat on my own hardware and possibly even software if I spent any amount of time doing anything not strictly related to the work I’m performing for the employer. Kinda like how a mechanic is nothing without tools and most maintain their set. I’d want no ambiguity - I was using my stuff to do my stuff and employer has absolutely no say in how I utilize my stuff when I’m utilizing it for purposes unrelated to them, and there can be no claim that they are in any way even tangentially responsible in me doing anything aside from the stuff they are explicitly paying me to do. “We provided them with software and hardware so we feel entitled to some ownership” lol