Current Game Toggle

There are two options. The first one would be to trigger whenever you change your category on Twitch. You'd use the Stream Update trigger and create an if/else-subaction (Core -> Logic -> If/Else) to check for: if gameName equals GameX do ActionY, where ActionY would contain all subactions to enable/disable whatever you want.

The second option is to check for when the game process starts on your PC. You'd use the Process Started trigger (Core -> Processes -> Process Started) for that. You can then specify the name within the trigger, it usually is just the name that pops up in your task manager. If there are multiple process names available, try them out one by one and see which one triggers the action.

Note: Some games with anticheat will prevent you from using the process as a trigger.