This is a serious question and happens almost every arc post time skip.
In punk hazard Zoro did basically nothing while Sanji had to face Vergo who was the strongest there.
In dressrosa Zoro didn't even get close to Doflamingo
In WCI Oda removed zoro from the arc entirely.
In Onigashima the yonkos only beat him because everyone else was beaten as well.
Now in Egghead Luffy deal with Kizaru while Sanji had to face Saturn
"muh... It's because Zolo is too strong and would beat them easily"
Yeah... NO
Because Oda made sure to place Zoro far from there and made him fight FUCKING Lucci LMFAO doesn't make absolutely no sense for Zoro to fight Lucci who is a fodder that Luffy just trashed a few chapters ago, if not to make sure Zoro is safe from the real danger.
It seems like Oda has is favorites.
In punk hazard Zoro did basically nothing while Sanji had to face Vergo who was the strongest there.
In dressrosa Zoro didn't even get close to Doflamingo
In WCI Oda removed zoro from the arc entirely.
In Onigashima the yonkos only beat him because everyone else was beaten as well.
Now in Egghead Luffy deal with Kizaru while Sanji had to face Saturn
"muh... It's because Zolo is too strong and would beat them easily"
Yeah... NO
Because Oda made sure to place Zoro far from there and made him fight FUCKING Lucci LMFAO doesn't make absolutely no sense for Zoro to fight Lucci who is a fodder that Luffy just trashed a few chapters ago, if not to make sure Zoro is safe from the real danger.
It seems like Oda has is favorites.