I believe WingetUI already runs in silent mode, it suppresses most windows in my experience. You can define parameters for individual packages, but not globally as far as I know, you'd have to check the documentation or their github to be sure.
Not sure if a hidden gem or not, but WingetUI is pretty handy. You can manage software in winget, scoop, chocolatey, pip, npm and .net with a graphics interface.
Then complain to the owners of the instance, defederation should only be the last option. Besides, according to your link the owner already solved the problem, so even less reason to do so.
You missed the opportunity to end in "What a shame, what a rotten way to die".