Hello, first of all, thank you very much for the super detailed answers. I take everything back and apologize for my hasty response.
It makes more sense the way you explain it now. I was thinking about two identical cases because then I can set up one flat and one at an angle. Nevertheless, with the dust cover they remain handy for traveling. There is also the 2x 104 Travel version from Intelligenz. Here's my other idea - that would be a future setup for me + plenty of space for more.
So far I've only used grooveboxes for my gigs. However, in the end it was more of a "playback" of previously produced things. I would rather practice something over and over again like I do with my guitar (I can memorize it well) and then perform it. Of course, you can also do that with semi-modular - it would probably be just as expensive.
metropolix standalone + cascadia + Model Cycles (as an example)
Since I come from a classical music background, an instrument for 4 - 5000 $ would not necessarily be unusual. But again, I would buy used modules if possible and I really like the Atlantix from the demos.
The idea of perhaps switching completely to modular at some point also seems very appealing. At the same time, it seems like opening Pandora's box, once opened there's no going back - of course that's just a perceived truth.