Here is what this is all about, in a summary form:
- Cables and switches themselves do NOT in any way affect the system.
- However, the noise that they and/or their power supplies may produce, MAY
affect sensitive analog circuits if they are placed close enough and may lead
to the mistaken conclusion that the devices & cables themselves are affecting
the sound.
As long as you buy cables and switches which are compliant with the 802 standards, AND they are placed away from sensitive analog signals, you will have no audio issues whatsoever.
Galvanically isolated (optically coupled) devices will also improve the noise floor.
Spend your money on better streamers or DACs instead.