I explicitly stated the non-white males or women got the worst scripts from Marvel itself, and that's why they lost viewers.
I really don't understand why people think The Marvels or Wakanda Forever were bad. The Marvels underperformed because of the strike and the lack of advance publicity, not because of the story. It was actually quite a good movie that got a bum rap, and I gather it's performed well on streaming.
And I've argued extensively in the past about why Riri was not "tacked on" to WF but was absolutely the right character to motivate the story, and quite an appealing presence as well. (I've been quite pleased with all the female "Young Avengers" they've introduced -- Kamala, Kate, Cassie, America, and Riri have all been delightful.) If WF had any problems, it was due to the need to adjust to the loss of Chadwick Boseman, and that couldn't have been helped.
In fact, I think your thesis here is completely wrong -- the films I've liked least in the past two phases have been Multiverse of Madness and Deadpool and Wolverine, both of which had white male leads. (Although I'm not convinced D&W really counts as an MCU film -- it's more of a Fox-Marvel Universe film that ties into the MCU while remaining tangential to it.) I also thought Thor: Love and Thunder, while better than Ragnarok, was just kind of middle-of-the-road. As for television, the biggest disappointment has been Secret Invasion, but I thought Loki Season 2 was a mess, so that splits the difference.