I got this resolved.
This comment helped a lot: Plex wont start normally after a clean reinstall and is stuck on getting ready - #15 by arythion
I manually set the DNS servers for my IPV4 adapter in Windows to 1.1.1.1 and 8.8.8.8 and then I opened the Setup Plex.html file again. It got hung up after a while, but when I reloaded the page I could see everything again. Not sure what was going on there.
