When you have multiple Apps on the Mac which all provide Quicklook extensions for the same file type, then I would assume that if I activate one of these Quicklook extensions in the system settings, this one would be used. But this doesn't seem to be the case.
It looks like the macOS just looks the very first extension it can find for a certain file type, and if this Quicklook extension is switched off, the file can not be previewed anymore. The macOS just doesn't bother to look for the other existing quicklook extension for this file, even if this other is enabled.
The only option right now to get this other extension to be used by the system would be to completely delete the first App, so its extension is deleted as well.
Is this really the way how it is supposed to work? How can this be fixed? Can I tell my users something else than "just delete the other App"?