If there will ever be a new Avengers movie , this is my prediction:
Captain Marvel
Scarlet Witch (not sure she'll be good or evil)
She-Hulk
Female Thor (Jane Foster)
Valkyrie
Black Widow (Yelena Belova)
Kate Bishop
Ms.Marvel
Wasp
Doctor Strange
Spider-Man
Ant-Man
Falcon
Shang-Chi
It's almost an all female team since they're running out of male heroes because most of them are either dead or retired.
There's a few more guys that can join the team. They are introducing Dane Whitman, aka The Black Knight, in the "Eternals" movie. He's been an Avenger in the comics. Bucky might not be retired so maybe the Winter Soldier could join. That Hispanic guy Torres in "Falcon and The Winter Soldier" (he helped Sam with some technical stuff plus Sam gave him his old broken wings) becomes the Falcon in the comics after Sam takes on the mantle of Captain America. Blade is coming to the MCU, we might even get Daredevil. Oh, and Moon Knight.
shareThat's a whole mess o' 'vengers. I reckon they will have only 5 to 7 at most. I think the core group will be
Captain America
Dr. Strange
Ant-Man
The Wasp
Shang Chi
Captain Marvel may be a part of the team, but they seem to have her mostly doing her own thing in outer space. The Winter Solider may be part of it. Chris Hemsworth may be back as Thor, depending on his contract. I think Spider-Man reverts to Sony after the upcoming film, so I doubt he'll ever be full-time Avenger. My Dark Horse Avenger candidate is Loki, who may redeem himself in the battle against Kang.
I don't think Female Thor will be a thing outside of Thor: Love and Thunder. At least I hope not. Would be cool to see Valkyrie though.
I would be more interested in seeing a Midnight Sons team up to be honest. The Avengers ran its course.