Hello.
I have no idea whether this is a new bug since the last update or if it's even being read in the Steam forum. However, it seems that the game crashes when loading a custom module. A workaround for this is to first load the official module, switch to the main menu, and then load your custom module. A solution to this issue would be desirable to avoid the annoying intermediate steps. Thank you.
Steam-Link: https://steamcommunity.com/app/1233530/discussions/0/6957562508419896410/
Edit:
By the way, the mentioned custom module is a very simple map, on which there is only a starting point for the player character and an enemy. So nothing elaborate or anything, which is why it should essentially be a fundamental bug with all newly created custom modules.