Use Dummy Display as A/V Output in Final Cut Pro

[samplue]

Would it be possible to use a dummy display as an A/V Output for Final Cut Pro? I've currently set up a 1920x1080 dummy stream to my Sidecar display, but unfortunately it is not available as a display/output option in FCP.
The dummy shows up correctly in system settings and FCP usually detects displays that have a standard broadcast resolution such as 1080p.

Are custom refresh rates possible on an iPad with ProMotion display or is 60Hz the only supported refresh rate?

[waydabber]

Yes, this is a problem, FCP just does not want to acknowledge virtual screens in general. Let's hope this will change in the future as with Vision Pro macOS will use virtual screens (to cast to the VP) more often so it will be more important for Apple to make things work.