Finally watched this movie and...
The movie looked small and claustrophobic with the entire movie taking place in the Quantum Realm because nothing looked like a real or tangible world. It looked like an episode of Star Trek half the time instead of a big budget Marvel movie. I've seen episodes of the Mandalorian that looked more impressive, production value wise.
The writing was not very good. Cassy was annoying. It got annoying hearing someone from the first movie go "DARREN!?" at MODOK because they repeated the same reveal three times that he's the villain from the first Ant-Man movie.
The movie picked up a bit when Kang finally showed up. Majors felt like he was in a different movie than everyone else. But with this and the Loki series, they've really shot their wad with Kang. We've already seen him do his villain monologues and being threatening. He feels overexposed already, which is different than Thanos, where he was largely kept in the background until they unleashed him full force in Infinity War. With your big bad, less is more most of the time.