The really fantastic thing about DLSS is that it can be updated with new functions and features and efficiency just from software updates. So a 2030 Switch 2 will be a good deal stronger than a 2024 Switch 2, just by virtue of improved DLSS.
DLSS is basically AI turning a lower resolution frame into a much higher resolution frame with very little computational cost.
It makes Switch 2 more powerful because, instead of needing to render a game at native 1080p or 1440p or 4k or what have you, the GPU can render it at a much lower resolution and then use the low cost DLSS function to raise it up to 1080p or 1440p or 4k or what have you. This then frees up GPU resources to do other things, like improved graphical effects or better textures.