Inazuma's main story quest was the most satisfying to date. My favorite part was how Raiden executed and killed Rosalyn. Genshin needs more moments like these where we get to kill off annoying, universally hated characters.
Mondstadt's quest is still the best written so far, but Inazuma's story was just really satisfying. These are two different things. The presentation of Mondstadt's archon quest, how Dvalin got poisoned, meeting Venti, Diluc, and Jean, and ultimately beating up Dvalin was well-written throughout and served as one of the best intros to any game.
Meanwhile, the Inazuma story was an ultimate culmination to the point where Raiden used the Musou no Hitotachi to kill Signora. It felt more like a build up and satisfying release.
Inazuma's story quests were by no means perfect. For example, Ayaka's quest was a complete bore and super lame. But if you want to talk about the lamest of the lames, look no further than Liyue's lackluster archon quest. Liyue's storyline felt like babysitting a grandpa and meeting people for tea. The only thing remotely entertaining in that quest was seeing zhong li retire and fake his own death. We need the same thing to happen to lee hsien loser in singapore and the li businessmen. They need to retire and die.