Thanks for reminding me of these snap apps @frederik-f . Just uninstalled the snap gnome-calculator and reinstalled the deb gnome-calculator. Now, the gnome-calculator actually starts snappy.
I use the calculator a lot during the day, so I even installed Galculator as the one in Ubuntu thought a bit, before starting. I forgot that this gnome-calculator is a snap. Thanks again for reminding @frederik-f here.
The other 3 apps can stay as snaps, for I rarely look at them.