A very interesting video, DF Direct comments on the Xbox presentation. It seems that they are unanimous in saying that the previous generation has a negative impact on Halo infinite ( meaning they don’t agree with Phil Spencer, and that making Halo infinite crossgen considerably lessens the potential of the game’s graphics). Many comments on the presentation, worth watching.
The two points I'd take away from this video, are that they mention development for Infinite started a long time ago just for Xbox One, and it was only later they suddenly had to re-work it for next-gen, which isn't some simple task. Also that the Slipspace engine just doesn't seem to scale as well as other engines by third party studios who know how to properly convert for cross-gen, like ID Tech 7.
This is also a game they plan to have ready by launch, so the closest comparison on PS5 would be Miles Morales Spider-Man-- standalone expansion of a PS4 title releasing at launch. But while I'd expect Miles Morales to look somewhat better, it'll also be a much smaller game in both scope and content.
If any of the other big titles like Fable, Avowed, Forza or Everwild also get cross-gen release, maybe you should wait to use those as examples, as they'll be around the same release window as the noteworthy PS5 releases, and are all being developed primarily for next-gen.