Of course 
I first ran these four commands and installed build 75, which is using the legacy desktop support. I got the issue about connection to gnome-3-28-1804 (my initial issue).
Then I ran the four commands again and this time I install the edge one (build 78). Unfortunately, I still get the issue about gdk-pixbuf-loaders.cache.
/snap/gnome-3-28-1804/current/usr/share/mime does exits.
The machine has kernel 5.0.0-25-generic, which is older than the working machine. I will try upgrading it tomorrow.
opera@opera-VirtualBox:~$ snap version
snap 2.42.1
snapd 2.42.1
series 16
ubuntu 18.04
kernel 5.0.0-25-generic
opera@opera-VirtualBox:~$ snap list
Name Version Rev Tracking Publisher Notes
chromium-ffmpeg 0.1 15 stable canonicalâś“ -
core 16-2.42.1 8039 stable canonicalâś“ core
core18 20191030 1265 stable canonicalâś“ base
gnome-3-26-1604 3.26.0.20191114 98 stable/… canonical✓ -
gnome-3-28-1804 3.28.0-16-g27c9498.27c9498 110 stable canonicalâś“ -
gnome-calculator 3.34.1+git1.d34dc842 544 stable/… canonical✓ -
gnome-characters v3.32.1+git2.3367201 367 stable/… canonical✓ -
gnome-logs 3.34.0 81 stable/… canonical✓ -
gnome-system-monitor 3.32.1-3-g0ea89b4922 111 stable/… canonical✓ -
gtk-common-themes 0.1-25-gcc83164 1353 stable/… canonical✓ -
opera 60.0.3255.56 x1 stable - -
opera-beta 65.0.3467.32 51 edge opera-softwareâś“ -
opera-developer 66.0.3512.0 78 edge opera-softwareâś“ -
Thank you very much today. I have to go now. I will come back to you tomorrow. Please free feel to leave messages.