Dude, wtf is that.
😂 lol but seriously I have the same non-producing and non-flowering issue with my NDM and many have told me they have had the same bad luck with NDM. I would say all things considered, including that wrinkly stinky thing, cut that abomination down! You got some kinda hudu-vudu on that thing! Also May have been a seedling and not grafted I think lots of nursery’s try to get away with that with NDMs because they grow true to seed usually. If that’s the case it could take 7-10 years to fruit. I’m about to top-work mine to a better variety I mean it’s a nice girthy root stock usually.
Just my opinion.