Physically, I think this feat here is Goku's best for heat resistance, but that's Toei Canon.
Generally speaking, Goku's been relatively unaffected by all kinds. The heat of Beerus' Cataclysmic Orb (which Old Kai said could evaporate anything it touches, likely including the planet, only burnt his clothes, he was unaffected by Lava in DBS Broly, the Hyperbolic Time Chamber's various environments only affected him as a kid, he easily took re-entry in Battle of Gods, he passively was fine despite the fact he was burning up the atmosphere as a SSG, and from an authorial intent standpoint, for the DBS Broly film Goku, Vegeta, and Broly
were envisioned to be fighting on the Sun but it was cut for time. (Though, obviously, that did not happen and we obviously shouldn't count it as a "canon feat," it does lend itself as a means of insight, especially when it is well known that the original script and film got cut down to what we got.)
That is to say, I'm pretty sure Canon Goku's heat resistance is actually very minimal pre-BoG if you don't include Ki Attacks that naturally generate Heat, (which we naturally don't do because that's impossible to quantify) due to the fact he rarely fights beings whose heat powers are at all worth talking about before he reaches Low Multi.