I think this is a pretty good guess, though I doubt they'll to Shang-Chi and The Eternals the same year. Both are "unknown's" and Marvel / Disney tend to play it safe, so they probably won't take that risk. I'd guess maybe that May 6th, 2022 date would be for whatever their big team up movie will be. Be it just another Avengers movie with a different roster or maybe some variant of Avengers like the rumored all women team or maybe "West Coast Avengers" or something like that.