My Alfred hot key is the shift key. I double-tap it, enter the first letter of the app I need (i.e. "d" for Devonthink), then it either launches the app or immediately brings me to the right Desktop Space where the app is already open and makes it active. Alfred has done this for me ever since I first installed it, years ago. There have been a few hiccups here and there but it overall it has been solid in this all through the years, upgrades, app versions, etc., etc.
Now, when I double-tap the shift key, it sometimes takes me to the app, and sometimes doesn't. Sometimes it takes me to an empty Desktop Space. This is why I had suspicions about my Mission Control settings. I just did it this very minute and it correctly took me to Devonthink but then would not take me to Excel in a different Desktop Space. When I try to go to Obsidian, it always sends me to the same blank Desktop Space. I usually have Obsidian set to full screen mode.