How strong could Batman become if given 7 years to train in the Dragon Ball universe?
How strong could current comics Batman realistically become if left him to train in the Dragon Ball universe for maybe 7 years max (because I think that's both not a ton of time but still enough for Bruce to train with a decent roster of Master), plus 7 is the magic number for DBZ so it's fitting)?
Assume he's aiming to become as strong as he potentially could by any (in-character) means necessary, regardless of if it's through Ki based training or external means like technology or artifacts.
The only rule to make this interesting is that he can only train with people he'd be able to reach and/or convince in-character.
For Example: Bruce would need a way to reach King Kai's Planet to learn the Kaioken and Spirit Bomb or a way to Planet Yardrat to learn Spirit Control and their techniques, and does need to convince them to train him.
But to throw him a bone as well, assume he also does have access to all his pre-existing connections in DC Canon, like the Justice League or Batfamily, to help him reach certain places, find certain artifacts, and meet certain people.