Lmfao!! Dude, read your post again. "Momo isn't an 8 year old kid". Wtf? How can you say that with a straight face? How old are you? if you are in your 20s or older, then you have to reevaluate yourself if you actually think "momo not being 8" is enjoyable or good story telling.
I'm saying that Momo isn't a little kid who can get killed easily anymore. He doesn't need protection. He's a giant ass dragon about to save Wano. Hence, Yamato doesn't need to protect him. She's probably there to guide him on how to create flame clouds, that's it.
Tunder Bagua is one of the fastest, if not the fastest known attack. Base Luffy could partially dodge it due to predicting it with FS. Katakuri's base speed >> base Luffy's and above that, he has shape shifting for even more efficient dodging.
Sure, with enough speed you might catch Katakuri sometimes, but
1) King is not near that speed
2) Katakuri has a second mechanism for protection (super hard Haki defense)
3) He can take a lot of damage (several blows from G4 and fighting with a part of his torso ripped out)
So youre using zoro feats such as withstand hakai for 1 second and getting seriously injured, and zoro‘s ultimate attack that couldnt even make kaido fall?…thats why u couldnt put him significantly above other YC1s cuz i bet they all could withstand hakai for 1 second too. Not to mentioned how easy for them to failed in making kaido fall