Well for sure an open world needs more resources than a "binary" game, but still, the Matrix demo shows the truly power of a "Next gen" game as I mean for this generation, and indeed, because it is just a demo, I expect more from a full game, because this demo is not super optimized and development was still in early stage for either the engine and the consoles themselves.
Speaking of Hellblade 2, taking as example a game of the same kind, The actual best of the previous generation, The Last of Us 2, the former truly demonstrate to be "a generation" ahead in every regard, and as such can be defined a "Next Generation game", if I then compare Horizon 2 with the first one, I can't say that, even though is quite good and advanced, but sorry I really cannot.
Forza Horizon 5 is indeed good, and they managed to make it scale quite well on next gen consoles, but it lacks of many things that don't let me state "it's a truly next gen game" even though looks quite brilliant. I've watched the digital Foundry comparision and I can definitely state that it is not more than the same game with higher settings on current gen consoles, not enough to declare it a next gen game.
Ratchet is good indeed, but I can't really take a cartoonish stylized game as example, even though it showcases some good technical goals