I thought the movie was alright. I liked Jonathan Major's performance as Kang a lot. But, I think Marvel missed a huge chance to make Kang as terrifying and compeling as possible. He said he killed many avengers, but we need to see him do it and feel it. All the main characters walk away and Kang dies, basically no stake in the movie.
This movie feels rushed, it should have been 3 to 4 hours long to elaborate the plot details.
Also, Kang being stuck in the quantum realm for this long makes him not as bright as he seemed.