If you haven’t already, could you see if the ‘Verify Integrity of Game Files’ option helps with your launcher issue?
- Right-click Vermintide 2 in your Steam library sidebar
- Select ‘Properties’
- Select the ‘Local Files’ tab
- Select the ‘Verify the Integrity of Game Files’ button
- When complete, close and reopen Steam
- Launch Vermintide 2 as normal