Lmao Poor judgement, He got embarrassed indeed,
If 1ms obito stomps on itachi, then its pure fan fiction that he says Itachi > 2 kamuis.
Kamui touch gg
Kamui Snipe gg
Sasuke was already inside of the ice to begin with, and inside Susano'o [His own technique]. There is no evidence of someone igniting flames where they cannot see or beyond an obstacle, which you can then in turn use as evidence of someone being able to use Kamui where they cannot see.
Being inside of ice does not negate that he had a huge chunk of ice right in front of him, and he used amaterasu right through it to a spot away from him
He could see through ice which is what enabled him to do it just like he can see through susanoo