My favourite game in the series is, undoubtedly, Assassin's Creed, the original one. No game after the first one ever really lived up to the fantasy set up by it; most didn't attempt to, either. The closest to attempt that, though marred by baffling design choices and a horrendously rushed development, is probably Unity.
While I am mostly down on the new Assassin's Creed paradigm, I still mostly enjoy my time with the games, though there's a lot of glaring design and narrative issues with them. While I don't expect Valhalla to resolve all of them, the development team's transparency on their attempts to fix them while still remaining in this mode intrigues me, and while I wish the games were something else entirely, I am looking forward to seeing what they've accomplished with the game, especially them continuing the sophomoric narrative of Assassin's Creed Odyssey. I am definitely looking forward to seeing how, if, they "fix" it.