There is no could be, the fight literally only lasted a few seconds. We have panels to prove it. Marco's statement doesn't deny anything. I seemingly can't find these panels of Queen fighting alongside King. If King says he's busy with Marco then it means he alone is busy with Marco. I don't get how Queen even fits into the equation. You're not making any sense.
Yup, Marco wounded King as well as Queen which is undeniable, but he ultimately lost while King is ready to go at someone even stronger than Marco now. Fighting them both at the same time is hard =/= I've been fighting them for the past two hours. Sometimes, you can tell your opponent is tough in under a minute, and Marco is fighting two YCs; he doesn't have to fight them for an hour to understand he can't fight them at the same time.
Yup, Marco wounded King as well as Queen which is undeniable, but he ultimately lost while King is ready to go at someone even stronger than Marco now. Fighting them both at the same time is hard =/= I've been fighting them for the past two hours. Sometimes, you can tell your opponent is tough in under a minute, and Marco is fighting two YCs; he doesn't have to fight them for an hour to understand he can't fight them at the same time.
In those panel Marco was seemingly winning it shouldn't hard if that was all about, but Marco says its pretty rough, that was mostly an outlier from Marco v King + Queen if not Marco would beat them at the same time if he could do that all the time but he couldn't. Marco was telling its hard to deal with both because of their early fights in 2 v 1 not when he was trashing both and making King internally bleed which is superior to bruise.
And, Sanji is going to win against Queen if assume the main crew will win their fights logic but same Sanji couldn't hold King and Queen more than 2 chapters. That should tell you how easily Marco would deal with King and Queen if it was 1 v 1.