Don't watch the special for this and just read the manga instead lol. You will save yourself SO much boredom. Of course, it has the same ridiculousness you'd expect of Heroes, but everything is much more fleshed out, explained, and less rushed. It's not perfect and is still an advertisement, but you kinda get the added bonus of seeing Nagayama's art improve, but that's really a fun feature of reading Ankoku Makai, to Universe Mission, to Big Bang Mission. The characters are still a tad flat, but more of their personality is shown than the snippets you get in the anime and arcade game. Also thismanga does handle the concept of Final Form Mira much better than Dragon Ball Xenoverse 2.

Overall, try to go into this wish a bit more of an open mind and you might have some fun. If, not, well, the other Dragon Ball mangas are always gonna be there.