Mouse stops working

I start the game and everything works fine until I load a map. Once I load the map, my mouse stops working. I can still run around and operate menus with the keyboard but the mouse does not move my character. After loading, I can still access the menus with the escape key. In this menu, I can move the mouse over the options but it doesn't allow me to click on anything.

I first noticed this issue a few months back and I asked for help on the Discord channel without any help received. I've played about 350 hours of this game since it released in alpha and I have loved seeing the progress and things added! It's truely an awesome game that I've not been able to play because of this bug. I've waited patiently for a fix but I'm starting to get hopeless. This only started happening when I got a new monitor. Acer Predator x35 (3440x1440).

Things I've tried:

-Uninstall / reinstall game

-New mouse & software

-Adjusted settings in game

-A series of alt-tabs in one particular testing incident resulted in my mouse working but I was never able to replicate

PLEASE HELP! I love this game and wanna play it again!