One Piece isn't that hard. When you're not sure about powerlevels, just look a the narrative Ain't no way Shanks looks bad before facing Teach.
Yeah agreed!
I mean look what shanks pulled
1) Stopped MF war and got WB and Ace dead bodies
2) split sky with wb
3) Audience with Gorosei
4)Got his film and because of it's promo oda made GreenBull back out of wano during his debut on panel
5) fought with mihawk -! fight which shook grandline and WB called them legendary
Narrative wise Shanks is set to lose to only two people - BB (most likely) or Luffy (if evil shanks)
As indigo said, nothing against Kidd. He will get his moments against RHP but he isn't beating shanks. He will be hype tool for shanks just like how law will be to BB as both shanks and BB need RPG
There is no way oda will make two of his best and hyped characters get defeated by some side characters like kidd and law after 20 years of buildup and before they got even their own arc