For the problem of inability to return from suspend,
Screensaver makes system unusable after latest Dom0 update (19-5) - User Support - Qubes OS Forum
We were able to solve the problem by applying the update here.
Ctrl + Alt + F2
sudo systemctl restart lightdm
I was logged in with this method , but then there was a problem with the volume control not showing the voice adjustment bar for all running Qubes, but this has also been resolved.