Well, I once set it up, and both the installation and usage were very simplistic. You couldn't specify anything during the installation except the drive where to install. And since you can't change app paths either (at least through GUI), I wonder if I can take advantage of a secondary drive. Maybe I'll just try it out again. I'm planning on setting up a home server but wonder if Umbrel is good for that.
Okay, that's more direct. I would assume all packages have static paths that aren't able to be changed through the GUI. I would read their docs and find out about that specific angle to try and sort it out. Also, symlinks are a thing, but you may create race conditions that particular OS may not expect if your mount timing is not absolutely bulletproof and perfect every single boot.