Many papers suggest that wormholes can be blackholes or even are... plus I wasn't really talking about 20ly here :/ I mean going into one can land you hundreds of light years away and even accidentally drop you very close to a white dwarf.
You'd get ripped apart approaching a black hole. Black holes are a mystery box of unparalleled gravitational force while wormholes are hacks in the fabric of space time that allow you to move infinitely in space without spending any time. However they are purely theoretical. Papers may suggest things about black holes but we'll never know for sure on account of we can't directly observe them. I think mini black holes have been made in particle accelerators but they decay almost instantly for whatever reason. I don't see why a black hole would be a wormhole but I'm not an astrophysicist and I suspect you aren't either. But maybe you're working on it