The how of this scenario is definitely fun to think about, but maybe the more important question is this: How are the characters who are left going to deal with the loss of their friends?
Marvel isn’t just going to kill all of its new heroes and franchises just for the hell of it.
You could spin that around and say, “OK, well, Marvel killed Black Panther, the most popular new hero, so everyone has to be coming back.”
Because that’s where the stakes really kick in, and we will see the emotional impact of how these deaths have shaken the MCU.