Hi and welcome!
I’m not sure if this will solve your problem, but you can try the following:
The issue might be caused by the fact that in your Game Mode, Player Controller, or Player Character, you have the Set Input UI Only node. This removes the input focus, which is why your controls may not be working.
If that’s the case, you can add a small script at the beginning.
Game Mode
Here, we take the current level name (Get Current Level). If the condition returns True, the Set Input UI Only node will be active. If it returns False, we need to set the focus back to gameplay input using the Set Input Game Only node.
Additionally, you can get the Player Controller, then use the Set Show Mouse Cursor variable and set it to True to ensure the cursor doesn’t disappear.
Another thing I noticed is that you have two different Game Modes for two different maps. This won’t work because you need to set one Game Mode as the Default Game Mode in your project settings. This will make it work across all maps.
Also, don’t forget to change Third Person Game Mode to MainMenuGameMode (the one assigned to your menu level).
I hope this helps you!