So shortly after my post, I got some fixes in this thread, then at some point the game broke again.
Yesterday, Windows 11 had a couple of updates, so I updated the machine, rebooted, and forgot about Harbinger as per usual.
Today, I went in, removed all compatibility settings from Harbinger, fired it up, and it WORKS again!
I'm 99% certain I still have the wrapper on it from before, so I'm wondering if the compatibility options messed with the wrapper in my attempt to make the game run better, and I had a self fulfilling prophecy of the game not working.
TL;DR - if you use the wrapper marked as the solution in this thread, do not have any compatibility options set for the Harbinger exe.