Putting RAM physically closer to the CPU does allow you to utilize the RAM better. It's physics.
If the RAM was 3x closer, would it somehow be faster? I'm looking for metrics. With the same stick of any given DDR5, how much performance loss is there on a few example motherboards of your choice?
My point, again, is that yes, on paper, shorter wires means less opportunity for inductance issues, noise, voltage drop, cross-talk, etc. But this is all on paper.
It's not like every motherboard manufacturer doesn't know what they're doing and Apple's brilliant engineers somehow got a higher clock speed than what the RAM is rated for because... shorter wires?
Case in point: DDR4 is meant to operate at a maximum clock speed per the specs of DDR4. However, on plenty of motherboards that are overclock-capable will support memory that is more than 3x the clock of what DDR4 should be capable of. How does this work with memory that is not soldered into the motherboard?
Additionally, without overclocking, the memory is designed to operate at a clock speed. Will shorter traces to the RAM magically increase the capable clock speed of the RAM? Are these the "physics" you're referring to?