im f2p i have Han, i dont have barrier ninjas and i dont use them on Arena, i use water main, 2 star yugito , kinkaku and Han (i get him by saving from the first day i play, didnt pull kage or other *, i do have sailor sakura get her by saving alot)

still i can beat, barrier setup, mei , hidan dp, susanoo sasuke , ay team. (most of them, but not roshi atm)

as for fighting sailor sakura, u c*e tobi or GNW kankuro, and u have danzo bruh, u cry too much.
and you dont have to have a high initiative, even if i got higher initiative, mostly i wait my enemy to move first to deal damage on me.