How to handle menubar applications that can "detach"?

[macintacos]

I use Fantastical to manage my calendar. 99.9% of the time, I just use the menubar application instead of the full application. The menubar application has a way to "detach" itself from the menubar and become a "normal" application, with window controls and everything, but if you don't detach it in normal circumstances, when the app loses focus the menubar app just goes away and there is no "window" associated with it. This seems to cause some weird interactions with AeroSpace when I try to invoke the menubar app.

To explain a little more what I'm looking for - I have three monitors to manage with AeroSpace: from left to right, it's my MBP screen and two monitors to the right of it in horizontal orientation. I have separate spaces disabled in my macOS settings, so I only have a single menubar in my "main" monitor in the middle of my view. If I'm in a workspace that's on the third monitor, for example, and invoke Fantastical by a keyboard shortcut, what seems to happen is that the application gets opened, and then the app is "detached" from the menubar and moved to that third monitor. What I want is for the application to be invoked in my main monitor (the one that has the menubar) and for the app to remain there in its non-detached state. Dismissing the app should return me to the previous app/workspace that had focus before I invoked Fantastical.

Is this possible? I kind of just want to have this application completely opt itself out of being "managed" by AeroSpace at all - not even in a "floating" sense, but I looked over the available documentation/issues/discussions and couldn't find any way to make an app completely "unmanaged" by AeroSpace.