How to disable ALL interaction until game loads?

[AndrewSidereal]

While my game is loading, I need to prevent the player from being able to interact at all -- e.g. opening the inventory, pressing "1" to use the first hotbar item, etc. What's the best way to disable ALL inventory interaction and then re-enable it after the game loads?

I experimented with disabling the EventSystem, but it didn't seem to address the issue.

 

[Sangemdoko]

How about disabling character input by disabling the Player Input (depending on the input system you use: UnityInput, UnityInputSystem, RewiredInput, etc...) component?