Have you tried updating UTM to the latest version? Many of these bugs have been fixed in newer versions. UTM doesn't auto update, so you have to check for updates yourself on their GitHub releases page: https://github.com/utmapp/UTM/releases
IMO it's not about running macOS on it but rather that there is a need for desktop-class features on iPad. Apple doesn't need to run macOS on iPad to add desktop-class features. I'd rather see those features added to iPadOS (as well as visionOS, which is clearly a derivative of iPadOS).
This is probably because those developers haven't added support for opening files in place, which has been available since iOS 9. There are a few other things (e.g. the way you call open/save dialogs) that need to be changed if you want to add support as well.