Nvidia's own list states 173 games total are natively supported or upgraded to support DLSS3.
Not all DLSS2 games can be upgraded to DLSS3, as noted by Nvidia's list of supported titles.
It sounds like you are conflating specific definitions and features that Nvidia created, see below.
"DLSS 3 is a revolutionary breakthrough in AI-powered graphics that massively boosts performance, while maintaining great image quality and responsiveness. Building upon DLSS Super Resolution, DLSS 3 adds Optical Multi Frame Generation to generate entirely new frames, and integrates NVIDIA Reflex low latency technology for optimal responsiveness. DLSS 3 is powered by the new fourth-generation Tensor Cores and Optical Flow Accelerator of the NVIDIA Ada Lovelace architecture, which powers GeForce RTX 40 Series graphics cards."