I wonder how long this has been "in discussion." This reeks of desperation and the mouse losing money.
Would probably help more if the MCU brought back the Russo brothers, over the original Avengers cast.
Building a film around Florence Pugh, Tom Holland, Chris Hemsworth, Sam Rockwell and a few of the GOTG would work just fine. Bucky, Justin Hammer and Drax haven't really had truly fleshed out character arcs, so that would be interesting too.
Pugh was the best "transition" character done so far. She's a phenomenal actress. The MCU should take advantage of that kind of acting firepower.
One of the biggest problems I see in the MCU is it's very dogmatic to it's "central characters" beyond all practical adaptation. Brie Larson in Captain Marvel was a dud. It just doesn't work very well. However Ben Mendelsohn was fantastic. So make him a central character instead. Luke Cage was exhausting. However Cottonmouth and his sister lit up the screen together. Find the characters that just work and fit and adapt to that. Daniel Bruhl is fantastic. Why do you need Kang ( because it fits a certain kind of arc/ESG mandate/"narrative" demand, etc) when you can just have Bruhl/Nemo back? But the current MCU won't do that, they feel the pressure to make sure Shang Chi is a new central Avenger character, even though that literally excites absolutely no one except maybe Simu Liu's own family.
Stick to your best actors. Stick to characters that show a good fit and work out for you, even if they aren't the "title" characters. Do I want to see more of Jessica Jones at all? Not really. But a season of David Tennant just destroying lives everywhere for sport, that would be interesting. Winston Duke is simply more charismatic and more plausible in action scenes than Letitia Wright. Why over complicate that for Black Panther 2?
As much as I think many sort of despise Cuse and Lindelof on Lost, at least when Michael Emerson/Ben Linus showed up and made everything exciting, they didn't mess with that lightening in a bottle. They shifted the entire storyline to adjust to keeping him central to the show's future.