Given how heavy Lumen/Nanite/VSM are on much stronger hardware, I expect we won't see much of them on Switch 2, at least not all together.
That said, it is early days for UE5 on the system; UE4 came a long way on Switch 1 over the course of its lifespan, and I'm sure we'll see improvement here too.
Having played Cronos, it's an okay experience on Switch 2, even though you can tell that as a day-and-date release it didn't have as much time in the oven as say Star Wars Outlaws or Cyberpunk. Resolution being the same in both docked and handheld modes is curious too and suggests maybe the port isn't all it could have been.
Split Fiction looking similar to Series S (albeit at 30fps) without the use of DLSS isn't a bad result either, though it is strange they opted for TSR instead of leveraging the system's machine learning capabilities.
It will be interesting to see how things go over time; there will likely be a lot of UE5 titles brought to Switch 2 over the course of its life, with a number already announced like Reanimal and Borderlands 4.