Disney has this perennial issue across all of its franchises now that they just don't want to commit to a villain protagonist or even an antihero. They feel like the MC of every story has to be presented sympathetically. Witness how they neutered Boba Fett, and made him boring. Or couldn't make Cruella actually evil. Or how more recent Disney/Pixar films (Encanto, Raya and the Last Dragon, Seeing Red, Strange World, etc) lacked any real villain at all.
I firmly believe if the Agatha Harkness show ever actually sees the light of day, she'll be morphed into a good character as well.
That's something that's been going on long before Marvel claimed the throne. Popular evil characters are turned into anti-heroes/given redemption arcs because well, popular. Such as Sylar, Spike, Venom (from the comics), The Terminator, The Riddler/Catwoman (also comics).