The simple answer, for anyone running Cyberpunk 2077 on an Nvidia RTX 40-series GPU is that you absolutely should be enabling Frame Generation in the game. And that's true both at the top and the bottom end of the GPU stack. Unfortunately, because it is based on the advanced optical flow accelerator in the latest Nvidia architecture, it is not open to any other graphics card generation.
Even if you're getting great native performance from your GPU, and aren't interested in using upscaling for a frame rate boost, then I would still be turning on Frame Generation. It's separate from DLSS, and so long as you're getting decent performance already will have a huge impact on the smoothness of your gaming experience without any discernible impact on visual fidelity.
At the lower end it's maybe a little more complicated. Frame Generation isn't able to give you 4K gaming performance at the highest settings on something like an RTX 4060 because, in a similar way to DLSS, it still needs something to work with. If you're getting a slideshow performance Frame Generation isn't going to magic that away, in fact it might even slow things down as I discovered when testing the RTX 4060 Ti.
But at lower resolutions, where you're getting a decent level of performance and aren't horrendously GPU bound, then Frame Generation will work well on even a lower-end RTX 40-series card.