If you can't do the things that are listed above, it's highly likely that the game files are corrupted for some reason. If they are potentially corrupted, then your game files need to be Verified. Go to Steam, Library, and Properties for the game, then Verify Game Files to repair your installation.

If this does not fix the problem, feel free to join the Discord and post a detailed explanation of what is going wrong and leave your DxDiag alongside your explanation for the Developers to get as complete an idea as possible of what is going on so they can attempt to fix any issues. The Developers check the Discord far more often than they do the Steam Discussion boards.

I hope you enjoy the game.