There is no upscale fps.
When you cap the framerate to 30fps it means the GPU is rendering over the target like 35, 37, 40, 48, etc and so it is caped to only output 30 and discard the rest.
When you uncap it the discard is cancelled and the output start to be what is being rendered: 35, 37, 40, 48, etc.
Upscaling refer to each frame… and not how many frames is being rendered… in fact upscaling has a overhead so doing upscaling will probably make the GPU render a few lower frames per second than if not upscaling… depend of course how costly is the upscaling algorithm to the GPU.
Plus reconstruction techs like DLSS are way more costly to GPU than upscaling… needs around 30% more GPU power… for example a 1080p target running at average 60fps will probably drop to around 40fps when using DSLL 1080p to 4k (Performance profile).
Of course the cost for DLSS 1080p to 4k is still lower than native 4k… if we take the 30% then it will be around 65% less expensive to the GPU than native 4k.