1. All my recent installs have X11 work properly, as long as nVidia or AMD display driver firmware is installed. To do this, read Installation.
2. Access to Snap applications via VNC requires tweaking permissions to access the X server.

Some interesting links regarding X11 and remote access.

• Remote Xfce session in a separate console
• x11vnc: a VNC server for real X displays
• How to share your desktop in Linux using x11vnc
• How to Run Graphical Linux Desktop Applications from Windows 10’s Bash Shell