After installing the display update my problems went away, but they're back now. Instead of waiting until Microsoft solves this problem I've search - and found - a shortcut to set the menu to automatically hide the taskbar again.
It's all explained here:
https://www.makeuseof.com/windows-11-hide-taskbar-shortcuts/
I realize this isn't a solution, but it's more than MS has to offer atm...
This is an excellent resource to put a band-aid on the issue, great find Bjørn.be. So, to those who are interested in this band-aid fix, something you can try is to create this shortcut that the guide linked above gives to hide the taskbar. Then once you've created this, open Task Scheduler and create a task to run this program when the computer is unlocked. This should make it so that when you log in, it will run and cause the autohide to activate. Like many of the solutions in the 22 pages of replies before me, this is a great temporary solution so it would still be nice to see Microsoft actually do something about this issue but in the meantime, I hope this helps.