Kata was only ahard match up for luffy because he was the perfect match up for Luffy's fighting style at the time. Luffy didn't have a effective way to fight kata and the structure of the fight was everything luffy could do kata could do better. Everyone isn't going to fight like luffy. Like how does characters we know are far above him beat him? How does wb or bm, or roger, or Rayleigh, or kizaru, or joyboy, or xebec or anyone without fs beat him?
There 3 ways to beat kata.
1. First is to use your own fs to counter his makes a normal fight. This is the luffy kaido and shanks route.
2. Secondly is to have great aoe to completely counter his body morphing ability. This is how characters like Akainu bm or zoro can beat him.
3. Last is to have great speed and coo to effectively counter is fs ability by out pacing what kata sees. Even a move as slow as wci g3 caught kata when he wasn't expecting it. High coo and speed would constantly have him on his back leg. This is how characters like sanji Rayleigh or kizaru can beat kata.