The problem could possibly be Windows Defender or some other antivirus program blocking access to the binary files.
As a temporary test, I suggest to disable any antivirus programs to see if Shotcut is able to start.
Some antivirus programs allow some programs to be excluded. Instructions for Windows Defender are here:
https://support.microsoft.com/en-us/windows/add-an-exclusion-to-windows-security-811816c0-4dfd-af4a-47e4-c301afe13b26