I currently use Ubuntu as the basis-distribution on my RPI to control my observatory. Would it make sense to switch to Stellarmate OS instead of ubuntu, and modify it as needed in my setup? Or would that possibly break something, prevent updates to install and so on... I could see the benefit of having the SM android app available, which I think is not possible on Ubuntu, and no need to mess with setting up a VNC server on a fresh install.
Well, SM is Ubuntu, so not sure I understand your question...SM is just Ubuntu mate with many extra astro features all bundled together... the latest version of SM uses the KDE desktop, but the Mate version is still used and available...
Stellarmate OS on Raspberry pi4b
Skywatcher EQ8 pro, on steel pier
Takahashi FSQ85, FS60cb & Meade 8” SCT (de-forked)
Starlight Xpress SXVR H18, SXVR M25c, Lodestar x2 Guide Camera
Pegasus Ultimate Hub V2 for all USB & Power
Pegasus focus motors on all scopes