The series tries to match the energy of the movies' humor but overdoes it. It's almost at parody levels, and most of the jokes are not as funny as the ones in the movies.
Also, I feel that the premises for a lot of these episodes are often a bit too random. The old What If comics occasionally had out there concepts as well but most of its stories were straightforward, like What If Hulk retained the brain of Bruce Banner, What If Uncle Ben didn't die etc.
Furthermore, the fight scenes for the first two episodes weren't very good either (I haven't yet watched the third episode). Agatha vs Arishem just devolves into them just punching each other.