The following are some reasons why Dr. Strange 2 was a failure.
Superficial + Superstitious:
The first Dr. Strange movie was a great movie, but this one felt so shallow. The whole movie felt like a rough copy of a comic book that wasn't made for cinema. Sam Raimi should go back to the early 2000s and earlier to make one-dimensional characters for blockbuster movies. This is where he shines the most: making zombie movies; and ironically in the movie, The Zombie Strange scene was one of the few good scenes.
Nothing but hype:
I'm disappointed at MCU. The great scenes of the movie were in the trailer to generate hype. The Loki TV show and Spider-man: no way home were far better in bringing the concepts of a multiverse to the masses.
Waste of potential and Lack of consistency with previous movies:
We could've had a real villain. honestly, the alternate Dr. Strange was far more impressive than Wanda for being the main villain. Only if he had more screen time. The music fight between the two Dr. Stranges was amazing. But this kind of fight should've been part of the main plot, not a side quest.
Wanda was all of a sudden buffed to hell. She was so powerful. her motivations for villainous acts wasn't convincing at all. Dr. Strange was nerfed to heaven! he was like a regular guy when fighting Wanda (if you can call that a fight). This wasn’t Dr. Strange that we knew, the Strange whose will was equal to Thanos.