For anyone else running into a similar issue to me, Adam helped me out and it turns out I needed to run the unblock command in PowerShell with elevated priviledges (run as Administrator). Once we ran that command and restarted the site in IIS, the dashboard started successfully.
The unblock command is in the documentation, but for completion’s sake here it is:
Get-ChildItem -Recurse | Unblock-File
Make sure to run it in the extracted PSU folder. Hope this solves anyone else’s issue too!