VirtualBox Windows Key Pass Through To Gnome

Yes. Open the VirtualBox Manager window, and go to "File" menu, "Preferences" (Ctrl-G).

Under "Input", uncheck the box labeled "Auto Capture Keyboard". There is no need to restart the VM if it's running, so this can be changed "on the fly".

ubuntu-20.04 as host and windows-10 as guest here.

I have similar problem but solve in a different way. I leave my guest fullscreen in a empty workspace and use hot-corners to switch between workspaces (guest and host)

This are my steps:

• add this extension https://extensions.gnome.org/extension/1362/custom-hot-corners/
• create workspace.next and workspace.previous scripts
• link hot corners to scripts and set "enable in full screen mode"

cat workspace.next

#!/bin/bash
CURRENT_WS=`wmctrl -d | grep \* | cut -d " " -f 1`
MAX_WS=`wmctrl -d | tail -n 1 | cut -d " " -f 1 `
NEXT_WS=$((CURRENT_WS+1))
if (( NEXT_WS > MAX_WS )); then
    NEXT_WS=0
fi
wmctrl -s $NEXT_WS

cat workspace.previous

#!/bin/bash
CURRENT_WS=`wmctrl -d | grep \* | cut -d " " -f 1`
MAX_WS=`wmctrl -d | tail -n 1 | cut -d " " -f 1 `
NEXT_WS=$((CURRENT_WS-1))
if (( NEXT_WS < 0)); then
    NEXT_WS=$MAX_WS
fi
wmctrl -s $NEXT_WS