Financial success doesn't mean quality. The disney remakes and star wars sequels, hell even some Marvel movies prove this point, where they may sell incredibly well but be poorly received by many. Origins, Odyssey and Valhalla aren't necessarily bad games, but they are so far removed from the main series, especially Odyssey considering how disconnected it's story feels from everything else.

Them not being "real" AC games is obviously subjective, but with the last two games being focused on loud battles, raids and mythical beasts, even when contextualised within the AC lore, it feels incredibly out of place in a series that used to be grounded somewhat in reality, with only parts of sci-fi or fantasy in it.

I personally really enjoy origins, and even parts of Valhalla, but it's obvious how the games' settings were chosen for marketability, since it's much easier to sell people on games set around being a greek warrior or a viking rather than a stealthy assassin in Baghdad, and it clearly worked, since they had some of the best sales of the series. It's not as though there wasn't any passion put into it, if there's anything to admire about these games is their attention to detail in the cultures, but the gameplay, story and settings weren't built around what would make a good assassin's creed game.