One of these will definitely work
Fix: Game Bar Not Working in Windows 10
The Game Bar in Windows 10 attempts to bring some of that Xbox magic to Windows PCs. By simply pressing the Windows key and G, you can summon the Game Bar at any time. This lets you quickly check your gaming-related notifications and activate features like game recording.
Most of the time it’s quick and convenient, but some users find that nothing happens when they try to bring up the usually familiar Game Bar. Or the Game Bar appears as expected, but some features don’t work.
What can you do? Actually quite a few things.
