Finally got mine to work but its the nuclear option.
First, I followed the process here to clear out my Battle net cache: support(dot)activision(dot)com/articles/deleting-old-files-from-playstation-4-and-xbox-one-consoles
Then I deleted the COD MW folder from my install directory (C:\Program Files (x86)\Call of Duty Modern Warfare) and uninstalled the Battle net app. I reinstalled the Battle net app and had to reinstall COD Warzone from scratch (took 2.5 hours total to download and update afterwards).