https://www.pcgamer.com/unofficial-monster-hunter-world-fix-addresses-fullscreen-crashes-and-cpu-usage/

Monster Hunter: World is a great game, but its PC port is just OK. Steam modder Kaldaien, who you may know from the 'FAR' resolution fixes he released for Nier: Automata, is working to improve the port, and recently released a mod pack containing a medley of fixes and features.

Initially, the 'Special K' mod pack focused on fixing World's habit of crashing when you alt-tab out of the game, as well as enabling HUDless screenshots and custom shading (which, Kaldaien advises, you will need to tweak because the default options look, uh, off). It has also been updated to improve CPU usage via controlled threading.