12 V-2×6/12VHPWR Cable power limit discussion

I have a Corsair rm650e (2025) psu, which includes a native 12v 2x6 cable, that seems to be limited to 300 w. I’m waiting on a 5080, which can go as high as 400w. So I have a few questions:

1. Is the provided cable able to provide more than 300w ? Or is the limit imposed by the sense wires?
2. If I were to buy another 12 v 2x6 cable with 600w rating, will that work? or is the port itself on the psu capped at 300 therefore the limit on the cable?
3. More of a broad question but how does the sensing cables work? How does the gpu detect the power rating for the cable?

(I know I can just use the adapter that comes with the gpu but it’s quite bulky)

Thanks in advance