To add, if nothing in the above article helps. Please try a clean reinstallation of Darktide, which involves deleting your AppData (please note you’ll lose any custom settings, keybinds etc. that will need to be redone)
I was able to continue playing after verifying the Integrity as the article you sent me recommended ;; that being said, you may look into adjusting the wording of the article as step 3 does not match the wording that Steam uses.