What I am about to write now is not a solution for your problem, but rather a workaround. Is there a particular reason that you installed KUbuntu 19.04? Perhaps you could use the Long Term Support (LTS) version 18.04 and try with that? I use that version for all my imaging with Ekos and at least all drivers are available. I never use GSC so I am not sure if it is available.
and all is being installed right now. No errors about missing packages or so. The installed version of gsc is 1.3~ubuntu19.04.1 so I am afraid that something is wrong with the OS in your virtual machine.
Wouter van Reeven
ASI6200MM and 7 slot 2" filter wheel with a SkyWatcher Esprit 80 ED on a SkyWatcher HEQ5-Pro
ASI1600MM-Pro Cooled and 5 slot 1.25" filter wheel with an 8" TS Ritchey-Chrétien on a SkyWatcher EQ6-R
I ran into the same issue and reverted back to 18.04 and all went well. I do however find that sometimes packages will fail to install if I do the entire command line but if I instead do a sudo apt-get install indi-full then a sudo apt-get install kstars-bleeding and finally a sudo apt-get install gsc that sometimes works better.
However with 19.10 it did not matter. Still failed to find gsc.
I have now created a VM based upon KUbuntu 18.04 LTS.
I installed the full INDI package including KStars/Ekos and all 3rd party drivers (GSC) with no problem
and the VM works flawlessly. So the problem ist really related to KUbuntu 19.10.