If it's really locked down, you can find USB devices for a few bucks that emulate a mouse and move by a few pixels every minute. Foolproof for those companies with nonsensical settings or nonsensical spying.

Deliberately bypassing that puts your employment at risk. There's a reason you're being forced to log in.

Maybe if you're slacking off, but if you're working on a project with 10-minute compile times, you can't really use the computer for anything else while it's doing that, and it's quite annoying if it decides to go to sleep in the middle of that because you haven't nudged the mouse recently enough.

Auto sleep and auto screen lock are two very different things.

playing something in windows media player also keep it open, or running a powershell script that presses F13 or scroll lock also works.