Sorry to hear this!
It appears that your game installation has a corrupted bundle file. Usually we’d recommend to Verify Integrity of Game Files, or try a clean game reinstallation.
In cases where the errors continue after trying this, we consider it to be persistent data corruption - which can, unfortunately, occur for a number of reasons.
We have a list of potential solutions which we’ve created based on what’s worked for players in the past, here:
Though I appreciate you’ve mentioned trying many solutions already (possibly everything in this article). If this is the case, and you’ve exhausted everything here, then I’m happy to contact Steam and request a refund on your behalf (providing Vermintide 2 was originally purchased through Steam). Let me know if this is something you’d wish to do.