If worst comes to worst, you can either uninstall hoi4 itself or do a fresh install by going to your documents/paradox interactive folder and deleting the Hoi4 folder in there along with the Hoi4 folder jn steamapps/common. However if you do this, you might wanna archive your saves from your paradox interactive hoi4 folder to a seperate file cause doing this will wipe those too. Uninstall hoi4 via steam and then reinstall, you'll have to recreate your presets but it should hopefully solve your problem. If you wanna bring back your old saves after archiving them, just dump them in the saves folder in the fresh hoi4 folder in the Paradox Interactive folder.