Has anyone had any success getting past the Windows lock screen?

Probably a dumb question. I'm trying to use my steam controller to log into my desktop PC which is next room from my lounge/TV setup. Close enough to use the pc-connected controller, but a pain to use it's keyboard.

I can get to the login screen on TV but can't get past the login PIN prompt because it requires keyboard and mouse. I can't control the mouse using the controller to even bring up the on-screen keyboard.

Weirdly when I lock the PC, it seems the controller mouse controls work for a few seconds on the login screen, until it seems they stop responding.

Is it expected behaviour that the controller mouse inputs stop working on windows lock screen? I've read somewhere about a "lizard mode" that still allows controller mouse input but this doesn't seem to be the case.

Is there any solution other than to disable login PIN, which I'd really rather not do?