I got banned once, and I think/guess/read from the Internet, the ways of avoid getting ban are two
1. don't touch the arena
2. dont spend too much diamonds in a short time, like gacha a thousand times in a day.
and back to 1. "not to touch the arena" is kinda tough since many characters needs to be unlocked through playing the arena, so... yes, to avoid ban you may need to slow down your play speed and also can't play some contents
hmm... do you got any ideas?