How to create splitscreen friendly navigable UI?

So I’ve ran into a problem when it comes to splitscreen UI. Basically, if your game has an inventory or other interactable UIs, and both players are trying to navigate them, only one can ever do something because there’s only one mouse cursor.

Problem example:
Player 1 using KBM opens inventory - Player 2 using gamepad opens inventory - Keyboard input takes control of the cursor for player 1 leaving player 2 on the inventory screen with no way to interact or navigate it.

There has to be a workaround because what’s the point of having splitscreen other than making simplistic games? Also, the lack of documentation and tutorials for this is depressing.

If anyone has any suggestions or ideas at all please let me know, this is a major hurdle for me right now.