This is a theory for who would replace the members of the Illuminati after Wanda killed the original on Earth-838. I think they'd be led by Cyclops, siding with RDJ’s Doom to help his own goals conquer earths across the multiverse. Doctor Doom, offered revenge in a form of deal to the Illuminati and hunted down every variant of Scarlet Witch until discovers the right one.
Awhile TVA who rescues and reach out the heroes (Avengers, Thunderbolts, etc.) from Earth-616 to form a new team of Avengers and as the Fantastic Four, Deadpool, Captain Peggy, etc join the heroes, the problem is: the Doom launch a preemptive strike on the TVA base, way to save each of their universe and half of the heroes fight Doom with his loyalty, Second-in-command “Victorious” (play by Ana de Armas) and try to convince them to see reason they’d present cause an massive incursion, while the other half deals with Illuminati who appeared to seek completed their goal finding the one Scarlet Witch (Earth-616) and providing intense moments and when help Doom exceeds the ultimate power, finally becoming a God Emperor.
James Marsden's Cyclops - Newest member and acting leader of the group who felt guilty wasn't present to stop Wanda massacring the only father figure in Scott's life. Who seeks revenge on Earth-616 Wanda and allows Doctor Doom's army's invaded the multiverse.
Emily Blunt’s Invisible Woman - Invisible Woman became the new representing the Fantastic Four on Earth-838 after Reed's death. Many of the Sue joined the Illuminati cause when before Johnny and Ben Grimm left Fantastic Four to due her actions desecrated the Reed’s memories.
Chris Evans Winter Soldier - In this reality, during the war even though he didn’t get the super soldiers serum. On the train where Bucky fell and “died” in the original film until he became the Winter Soldier, Steve takes the place of the sacrificial soldier. Steve falls into the hands of Hydra and is turned into the Winter Soldier. Many years later after World War 2, Captain Peggy freed Steve under Hydra influence and became the top enforcer for Illuminati.
Mordo (chiwetel ejiofor) - the only member of the original Illuminati who was present during Wanda's attack to survive, he is also desperate to take up Dr .Doom's deal to Invade Earth-616 and locate Wanda.
Teyonah Parris Captain Marvel - She could've gone through an upgrade after Wanda deleted the Illuminati. Take her mother's place.
Serinda Swan Medusa - with the death of her husband, Medusa was able to take over Attilan and now rules the Inhuman Kingdom.
If the incursion Doctor Strange caused was between Earth-616 and Earth-838, I think they would make cool villains for either Avengers: Doomsday, Doctor Strange 3. Let me know your thoughts.