Nothing supports Zoro being weaker. The fact Luffy and Law needed gladiators help when Doffy needed Fujitora help is quite the opposite.
Luffy and Law had difficult fights until Rooftop at Wano. Zoro had none. Of course Fujitora was difficult but they didn't fought to the end. One Piece is clear that those difficult fights is where you grow the most. So Zoro had little grow until Wano when Luffy and Law had way more grown. And still at Rooftop we could see how Zoro was way superior to them.
Doffy didn’t need Fuji to step in to defend himself against Zoro.
He was just aura farming to show off that he had an admiral on side.
I’ll say, it’s made pretty clear Zoro wasn’t on Luffy’s level in Dressrosa, and even up to act 2 in Wano.
Zoro bested guys like Pica and Killer pretty handedly when he got to take the fight seriously, but they weren’t completely easy fights for him. Hell, even Hawkin’s straw man was able to push Zoro.
Pica was able to hold his own against Zoro for a pretty lengthy period of time, and made Zoro exert himself a fair bit.
Same goes for Killer. Zoro didn’t have have three blades most of the fight, but Killer didn’t have his weapons either.
Zoro was clearly stronger than your average new world super nova level pirate at the time, but I don’t see him being able to beat commander level characters before act 3.
He got stalled pretty effortlessly by Kyoshiro(who I think is probably on par with the base mink dukes and Ashura douji), and although he definitely finishes those fights flashily, it typically involves a big move.
Meanwhile, Doffy defeated someone like Smoker in an instant, could have easily slaughtered Kyros, who was a guy who overpowered someone with the same ranking as Pica, and who actually specialised in swordsmanship, and defeated Sanji and Law without losing much if any stamina.