They do a good job in this one of bringing you up to speed. I don't have to have a ton of backstory to enjoy what they offer with 5. I know some titles are region-specific, but I have a feeling you'll geet DMC 5.
And yes the DBZ is a fighting game, but it's not just 2D side-to-side fighting.
This makes it more interesting. It's kinda difficult to play when you don't know the backstory so this is really a plus for me, not needing to know the history that much. Sadly, I just checked and it's not available here.