1) PSUs produce their own coil whine. How much depends on the quality, type, specs, and size of the components used.
2) The graphics card also produces some coil whine. Again, how much depends on the quality, type, specs, and size of the components used.
3) Interaction between the PSU and graphics card can result in louder coil whine.
4) Coil whine is related to frequency and current.
5) Rapid changes in current demands (such as rapid load modulation when transitioning from low power state) is a major contributor to piezoelectric noise (some capacitor types are more prone to this).
6) As ripple frequency and other sources of power related noise can impact the level of coil whine, some combinations of psu and graphics cards may exhibit more noise than others. For a vendor, it is very difficult to account for all permutations because cost is a factor if you want to increase resilience to coil whine. There is only so much a vendor will or can do.
7) As current plays a part, the amount of audible whine will vary from system to system.
9800X3D / 6400 CAS 28 / ROG X870 Crosshair / TUF RTX 4090