I can see why UV's can be nightmarish. I'm starting to try to figure out how to work them and I brought in my first model I made (my crash course creation into C4D) and it looks like an army of spiders made a massive size web.
First though, I tried opening it in Substance Painter, lol. That did not go well. It instantly locked up, AND, my graphics card drivers crashed. hahahahaha
For your entertainment and horror I have attached a screenshot of it.