However they do it, Kang has to be introduced to everybody else before Ant Man. Remember, Ant Man is supposed to have all the heros in the flick like Cap Civil War. There is no way they don't introduce Kang in some way before Ant Man drops.
Remember, Loki and Sylvie changed a lot of shyt killing Kang. Maybe at the point of the Thor release, Loki has became the leader of the TVA and might have the ability to enter the realm from the multiverse.
However they do it,I can't wait to see that shyt. I'm expecting Thor 4 to be a GOAT level Marvel flick because of how fukking dope Ragnarok was, it's one of my favorite movies of all time. There was no Marvel flick, from start to finish, as enjoyable as as Ragnarok. When Hulk popped up, that shyt too I'm the film to another level, and it was random and unexpected.
I think they will handle the Loki situation in a similar fashion.