Hello,
Sorry to hear you are having trouble.
As you may already know, this is where UWP app visibility is set:

If you are comfortable looking at your registry, this is the location of the setting and what it should be to not show:
[HKEY_CURRENT_USER\Software\Stardock\Start8\Start8.ini\Right]
"21"="0"
You can log out / in after setting it are restart Windows Explorer:
https://cdn.stardock.us/support/uploads/2019-07-26_14-54-09.mp4
If you have it set, but its still showing, perhaps a purge / reinstall is in order:
https://forums.stardock.com/486022/start10-support-faq#reinstalling
That said, any app that is indeed a universal one, would show there. That one is, a UWP app, is not always clear (calc is one for example).
Sean Drohan
Stardock Support Manager