i mean, you cant destroy fire with heat/ hotter things
as you cant destroy sound with ultrasound

but it isnt about destroying, think about it in this way:

the lava guy is milkshake, and ace is milk. even if you add the milk to the milkshake its still milkshake (what im trying to say maybe he just 'consumed' him or something, couldnt find better word for that but hope you get my point)

oh and also it could just be the the admiral guy used haki and he just was simply stronger than ace

and also the idea about the endless swamp being space of him free to use sounds believable too

yes but that fire isn't just fire. it is Ace himself. Who can only bring the heat of his fire so much. Anything hotter will actually burn him..

you cant burn fire coz its already burned lol

but you can raise the temperature of fire. And Ace couldn't handle the heat

you cant raise the temperature of the fire only the heat

and the heat wont affect fire at all ...

that makes 0 sense what so ever. the heat comes from the fire itself. so an increase in heat means an increase in temperature of the fire. where the Lava comes in contact w/ the fire there is an extreme temperature increase. one that is obviously too hot for Ace to handle

THE TEMPERATURE WONT HURT FIRE

But Ace isn't just fire. he is human. and obviously there are limits.. nothing in this world can hurt fire as fire isn't a living thing. but Ace is.

you guys don't know shit about that, go study it and then come back to comment on it