DBZ will sell pretty well. There are some people who think DBZ is stepping on Xenoverses trenches and probably won’t buy due to that, but other than that should do well. Graphics that have real money and work out into them plus the most relevant DBZ characters pretty much all showing up is a good sign for good sales.
As far as competitively will likely be the most popular game competitively they’ve ever had. Finally releasing a game that won’t just cater to hard animu lovers. DBZ is a bigger property that people who don’t give a shit about anime at least used to watch or know about. If they like fighting games that can get them in competitively. Giving room to get those people in competitively that may not have thought about it with a standard anime game.
Marvel is the broken game without many rules so set play is expected. The way the game is going you’ll likely have to have a character with an invincible level 1 to not have to play the “who gets to setplay first” game every match. Lot of the setplays people are getting around in tournaments now can be mitigated with invincible level 1. Plus stone storm guard cancels which make you completely invincible and work on incoming. Same like how everyone says you die in one combo in Marvel 3, but realistically hidden missiles and phoenix kept the game 2 player ish well enough.
I expect DBZ to be set play heavy since there’s never been an arksys game that hasn’t been. Especially with the assist call system it’s almost guaranteed to happen. The nice thing about DBZ though is that after a character dies the round is reset (I’m assuming this happens on point characters, but not sure about assist deaths). I don’t personally care for it much since it breaks up the action too much and reminds me too much of the constant clash battles in Injustice (especially when the clash animations in DBZ are all the same generic forearm bump thing), but competitively it works.
I prefer my edgy Capcom characters and full on oppression session so I’ll stick with Marvel, but it should do well.