Force time curve shows you what happens to force depending on the time available to produce a movement (e.g. 1 second vs. 0.2 second). This is useful if you’re comparing very different types of sports (e.g. powerlifting vs. most sporting movements) or even different athletes.
So one athlete might have a higher max force capacity but it takes him 2 seconds to get there. An athlete with a lower max force capacity might still win if there are only 0.2 seconds to generate force b/c the second athlete has a higher RFD.
Force velocity curve shows how force production capacity changes with speed of movement (e.g. slow vs. fast). Useful for comparing different, well, speeds of movement in the same exercise. Although the in-vitro force velocity curve has some issues when you extrapolate it to the whole body.
I have no idea if that even begins to address what you’re asking.