The ZoteroQuickLook plugin (https://github.com/mronkko/ZoteroQuickLook)n
has been difficult to maintain for sometime and has been having worse and worse performance on macOS due to changes in the underlying Apple utilities.
The new Zotero PDF reader is really fast, so most of the value ZoteroQuickLook is gone. It is usually faster to open the PDF reader than it is to open either an external app or any QuickLook utility.
One downside is that many users of QuickLook are accustomed to the spacebar keyboard shortcut for previewing files. Would it be possible to make the spacebar open a file in Zotero (ala Enter/Return), either by default or as an option?