I certainly don't expect it to be putting out native 4k in most games (at least, 3d ones). But it should at minimum have 4k output, and ideally HDMI 2.1 output because:
- Higher res media apps are a freebie as long as the chip supports the media playback (and it should, Nvidia shield tv can do 4k).
- VRR support is great for people with new TVs. Going into the future this will become more widely available.
- Some games are extremely light - ports of ancient games, some indies, 2d games.
- Even in sub-1080p games, having a 4k UI & text looks crisper and better in the game.
- With a more powerful switch, resolutions north of 1080p can look very good on a 4k TV. 1440p with TAA looks very good in some games on a 4k screen, even if it's not "full 4k" - it's still much better looking than 1080p. Hell, even just native 1080p with a 4k ui looks much better than 900p and a 1080p UI!
I do not expect DLSS support, imo that's a pipe-dream for a mid-gen refresh. It requires your game be implemented in a pretty specific way that Nintendo games themselves probably aren't (they don't seem to be using TAA etc unless it's an Unreal Engine Yoshi game, so the motion vectors may not exist in-engine). I'd love to be surprised on this, but that feels more like a Switch-2 thing, rather than a Switch Pro thing.