It's Arena, everything can kill fast there. Susano Itachi or Kakuzu with breaks can kill you turn 1 with auto attacks, even old gnw 1010 team used to kill people on turn 1

Outside of Arena though his damage is not even high i would say, comparing to other popular move 1 ninjas.

Well arena is a bit like rock paper scissors so thats normal if you have team to counter one thing, other stuff will be annoying. One team i use Shizuka/Kisame/Ningendo does rly good vs 6 path and minato but not so good against Kakuzu. Halloween Kimi would be good counter to him as well, can block his auto atacks which hurt a lot and ruin his mystery.