what a shitty port, it should be warned on the gog game page
let I go uninstall
I am the same typically, but this game really doesn't need a mouse for anything.
This plays like an SNES game, like Final Fantasy VI. You typically zoom through menus using up down in turn based combat, and then you use wasd to walk around.
Finish the prologue and you'll see what I mean. It was also made on PC first so not a bad port.