Did u also try to “reset” the local storage where the local save states are stored?
You find it at: c:\users\YOUR_USERNAME\AppData\Local\Game Dev Tycoon - Steam
You can simply rename “Local Storage” to whatever and see if the game works with the mods after that. Be aware, that you’ll lose all save states.
By renaming it back, you have your old save states back.
As @SirEverard already mentioned, it’s a good idea to have Steam Cloud disabled when using mods, as it will load/save states from the steam cloud.