I am also unable to acquire the last ravenous worm 9/10. I am on the same character i started with. I completed tithing worms and switched back to path of resolve. I was able to pick up two ravenous worms in the mausoleum area and hull breach respectively after the switch. With the help of video guides and multiple nether runs in advanced-private mode and expert mode-private, I checked all locations and was unable to find the last remaining worm. Perhaps it was collected and did not count unsure on how to proceed