Eternals Shouldn't Be Avengers In The MCU: They're What GOTG Used To Be

screenrant.com:

When Eternals debuted in the MCU many wondered if the new heroes were to eventually join The Avengers franchise, but they're actually more akin to The Guardians of the Galaxy–and should stay that way. The Avengers are left in a state of disarray after the events of Avengers: Endgame. With Captain America, Iron Man, and Black Widow out of commission there is much speculation as to who will lead Earth’s Mightiest Heroes next. Audiences suspected that Ikaris or Sersi could now lead the Avengers, but given what happened in Eternals, that is not likely because Marvel needs them to fulfill a different purpose.

Eternals revealed that their superhero team was created by the Celestial Arishem to prepare for the Emergence, or the birth of a new Celestial being, which would destroy the earth in the process. By the end of the film, Sersi and several other Eternals had foiled the Emergence, but Arishem then abducted Sersi, Phastos, and Kingo into a space singularity to answer for their actions. The post-credits scene revealed that, aided by Thanos’ brother, Eros, Thena and Makkari vowed to find their lost comrades. 

Related: Eternals' Ending Made One Unanswered MCU Mystery More Terrifying

If and when the Eternals are reunited, however, they shouldn't join any future Avengers movies. The MCU needs a superhero team that is entirely set apart now that the Guardians of the Galaxy have fought alongside the Avengers. Before the events of Avengers: Infinity War, the world of the Guardians was separate from that of the Avengers, and plenty of audiences even thought the Guardians of the Galaxy were better than the Avengers. However, after Thanos’s journey to find all the Infinity Stones, the Avengers and Guardians essentially merged to fight