You can only meaningfully determine that if you assume the die is more-or-less the same between the two versions. It is not; the M3 Pro has many changes, the perf/efficiency core ratio is different, they have different amounts of per-core cache, max clock rate, etc. That gets bigger as you move away from the CPU cores (e.g. the GPU is a big architecture change.)

For example, the M3 Pro has 6+6 P/E cores, versus the M2 Pro's 8+4. That is a big change that impacts performance, but can only be truly measured "globally" on a specific workload. The M3 Pro does do better for many workloads despite that. Maybe we could assume the improvement in transistor density gave them enough performance uplift, they were able to get rid of 2 P cores and still come out ahead. Does that mean that 3nm is "bad"? No, it meant it was good enough that it allowed them to make a different tradeoff.

"How much uplift comes from this one exact thing" is not really a super simple question to answer in this case, unfortunately, and there are many factors to control for.