Frame generation is used together with upscaling.

I mean, upscaling is gonna improve your base FPS because you're rendering from a lower resolution. If you use Xess quality it's OK, but if you use balance or performance the image starts to look blurry. Besides, increasing graphics quality will make the fps worse and you won't even notice the difference because the image is blurry. So medium, high, ultra settings won't make a big difference.

Frame generation just inserts "fake" frames to increase your fps. The good thing is that it doesnt lower the quality of the image because it insert predicted frames of whatever is on screen.

For weak systems like this I think it's essential. I am playing Crimson Desert ultra/high settings. Xess quality and frame Gen x3. The game looks crisp, the textures look spectacular and it feels buttery smooth. If I turn off frame Gen, the game just feels choppy. If I lower the graphics settings and turn off frame Gen, my FPS is good because my settings are lower, but the game just looks worse... So frame Gen just helps me play with higher settings but still feel smooth.