I can see his regen lasting for a while longer, but on the offensive department it would take a lot of time as well for him to put down King and Queen.
We've seen some of his named moves against their base forms and he's only doing superficial damage like scratches that are childs play for the Ancient Zoans and don't even serve to inconvenience them going forward.
That's why i say it would take some degree of high difficulty to put either King or Queen down, those battles would last for a long time and Marco would have to outlast them and chip at them to have them defeated for good.
severe marco downplay imo.
he wasnt just doing superficial damage. that move was strong enough to send queen flying into the opposite building. if anything he was overpowering the both of them in those clashes at the same time while being nerfed.
at marineford, he was sending kizaru crashing into buildings, aokiji flying etc.
he also clashed with big mom albeit temporarily.
he is more than enough strong offensively to put them down. and there's also a possibility he'd go to the rooftop to fight kaido.
I think Zoro and Sanji will clearly surpass Marco's offensive output in Wano, but Marco will make up with his broken recovery to remain ~ Sanji ( give or take either way small margin ) and not far bellow Zoro.
no. sanji isnt there yet.
the gorosei expected marco to become a yonko and to defeat blackbeard. do you see post wano sanji doing stuff like that?
shanks offered pre marineford marco a place on his crew. do you see post wano sanji getting such offers from shanks?
as i said, EoS sanji or even the sanji that's gonna fight in that war, surpasses marco. and that war is like 2-3 arcs away. but post wano? i dont think so.
for the record, i think post wano zoro is only slightly above marco (give or take) so you should see where im coming from.