I've found several older posts of this issue for various combinations of macOS and VMware Fusion where Windows 10 VM goes black but none of those fixes (e.g. disabling 3D graphics in the VM settings, enable 'Recording' in the Mac Security settings, ensured latest VM tools is installed, etc.) appear to work. The challenge is that it is not reproducible but instead happens at random.
Sometimes Windows VM powers up and everything is fine for several minutes - sometimes hours - but then the VM window flashes black - especially when using any browser for Teams or Outlook. Other during Windows VM power-up the window appears during login but then goes black. When powering down while the window is till black, the Windows log-out screen will suddenly appear.
Other times the Windows VM goes black after a period of inactivity and no mouse or keyboard action brings the display back to normal, but it sometimes just re-appears after several minutes.
Has this issue ever been completely resolved?
What Mac model and graphics card are in the Mac you're running Big Sur on?
No this is still an issue.
MacBook Pro (Retina, 15-inch, Mid 2015)
Intel Iris Pro 1536 MB
I've fiddled around with the VM's display settings and right now I actually enabled 3D graphics with full retina display, unchecked adjust automatic user interface size and Fusion display preferences for VM rez. I don't get as much flickering and it is actually usable but if I leave the VM idle for several minutes the screen freezes. I have to suspend/un-suspend the VM to get it functional again.