So I've been doing some research due to the stupid memes in this thread. Endeavors flames at max output are calced at 55000-66000 °C.

https://deathbattle.fandom.com/wiki/User_blog:Padureanvladioan/Endeavor%27s_Analysis_-_Abilities,_Skills_%26_Feats_-_Personal_Work#1

"x10" to "x12" times the sun's surface temperature. Dabi's firepower is stated to be greater than his fathers, and Gigantomachia shrugs off his attacks without being scathed. This would make him more durable than a Viltrumite.

And then Mina comes along and fucking melts down his arm like NOTHING. Holy SHIT.