if they keep everything as is and kang is still the villain i think what will happen is that they'll fail in kang dynasty and then we'll get Battleworld.
which is basically an area where all the heroes are displaced in different lands in areas then they have to come together to defeat kang.
you have to divide up everything like this
Cosmic Heroes
Guardians(maybe), FF, The Marvels, Eternals
Earth Heroes
most of the Avengers, but more notably the science-based heroes like Iron Heart and Iron Man who will come back for the movie
Magic Heros
Scarlet Witch, Doctor Strange, etc
then you have the horror side which may or may not be involved
it takes all of them to work together to defeat Kang since at that point Kang will be able to combat all of them with their powers.
the leaders will be Steve Rogers and Sam Wilson Captain America
not all heroes will be as important just like before