In my opinion stage manager is a fail and does what it wants way too complicated. Instead of having a computer-like system for multitasking you have to remember which app you opened beside another one. This creates many „desktops“ when coming from the traditional macOS experience. When you want to go back to an app you opened some time the first thing you automatically do is look through the recent apps on the left side but when the app is too far back you then have to open it again from spotlight or the home screen which costs so much time.
I hope you get what I mean.