Luffy being much stronger than Zoro doesn't make Zoro worthless. Zoro is still a beast and can take on other strong characters that the rest of the crew can't. Luffy just has to take on the strongest since he's the strongest, Zoro can get the next guy
You don't get the point man.
Unlike other guys like Sanji, Robin etc, Zoro doesn't do anything.
Zoro's role at least used to be that he could kinda do things Luffy can't when push comes to shove (be it either because he's incapacitated like in TB. Or in combat due to matchup issues back when haki wasn't a thing, like against Mr1). To fulfill this role, he had to at least be somewhat relative to Luffy even if weaker, not fodder relative to him. Which he was pre TS, as hinted in whiskey peak and TB.
What really is Zoro doing in the crew at this point, if he's low diff material for Luffy?
His haters always claim he's just "badass bait" with no real function, it seems like his existence at this point is closer to that.