I saw a post on Reddit that said "say what you will about Phase 4 but there's no denying we've gotten some phenomenal villain acting performances". I have to say, I really agree with that.
Sure, the villains in Black Widow, Falcon and Winter Soldier, Eternals, and Ms. Marvel could have been better but everyone else has more than made up for them.
Kathryn Hahn's Agatha stole the show in WandaVision
Jonathan Majors introduced as Kang was one of the best parts of Loki
Tony Leung was awesome as Wenwu in Shang-Chi
Pretty much every villain was great in No Way Home, especially the GOAT Willem Dafoe's Norman Osborn
Even though he was more of a glorified cameo in Hawkeye, Vincent D'Onofrio's Kingpin will always get a pass
Arthur Harrow was a bit underdeveloped in Moon Knight but Ethan Hawke still made the most of it and brought an interesting character to the table
Elizabeth Olsen really embraced Wanda breaking bad in Multiverse of Madness and gave a terrifying and heartbreaking performance at the same time
Finally, thoughts on Love and Thunder may be mixed but Christian Bale's Gorr has been unanimously praised across the board for obvious reasons