In the Marvel Cinematic Universe (MCU), the Infinity Saga has ended and the Multiverse Saga has begun. Avengers Secret Wars will be the conclusion of this Multiverse Saga. As this is the last film, it will be a vast multiversal event. Avengers Endgame is an inter-universe story but Avengers Secret Wars will be multi-universe related. You are definitely going to see the Variant of all the Heroes in this movie. Apart from that, Kang Dynasty will also involve the multiverse more.
There are no movies in Phase 5 that tease the Multiverse too much. But the multiverse should be teased from some film. The film that will be the beginning of this multiverse saga is known as Dead Pool 3. This information is not confirmed but received from some reliable Insiders. The biggest multiverse storyline will start from this Dead Pool 3 movie. TVA(Time Variant Authority) from the Loki series will be more involved in the Deadpool movies because this Dead Pool 3 movie is all about time travel.
Multiverse is definitely an Incursion Event. An Incursion Event is when the boundaries between two realities are affected and the entire reality is destroyed. Dead Pool 3 movie is a reason for this incursion event and the entire relationship may be affected. This Incursion Event does not happen immediately. Little by little the whole reality will disappear. From now on, all the films coming from the Marvel side will be related to the incursion event.
Dead Pool 3 is followed by Fantastic Four. Information has been leaked that Galactus is the villain in this film. The next film Shanchi 2 will also be related to the multiverse. Movies like Armor Wars and NOVA will be released in Marvel Phase 5. Just like Thanos won in Infinity War, there is no chance of Kang losing in the Kang Dynasty. The conclusion of this Kang Dynasty movie will be a lead-up to Avengers Secret Wars. Kang will join the worlds not destroyed by Incursion to form Battleworld. It remains to be seen how Marvel Phase 5 and Phase 6 will play out.