Being direct rivals to Luffy doesn't put them above Zoro.
They need to combine their strength to accomplish what Luffy is capable of doing ALONE.
BB is Luffy's only rival who can stand up to him.
I don't disagree with that. Still it doesn't make them > Zoro. There is no evidence that Shiki or Linlin were stronger than Ray and they were also Roger's rivals.
Law and Kid are not as strong as Luffy yes.
But they aren't below Zoro by any means.
They are fighting Big mom and push her to go serious to the point that she even sacrifice her 1 lifespan
Even if it's 2v1, that's better than fighting King on equal ground.
"There's no evidence that Linlin and Shiki are above Ray"..........yes right imagine Linlin and Shiki fighting teenage Marco, Jozu, Vista etc for 3 days.