It appears that your GPU is below the minimum requirements for Vermintide 2, so this could be resulting in the crashes you’re experiencing.
Though, you mention that Modded realm is working, which indicates the issue may be related to our Easy Anti-Cheat service.
It seems you’ve already tried all of our usual recommendations in this situation, so I’m a bit of a loss at what to suggest.
In this instance, I’m happy to contact Steam and request a refund on your behalf (providing you purchased through Steam originally), please let me know if this is something you’d wish to do.
Sorry I’m unable to be of more help