I comprehend that you don't understand USB risers are not electrically isolated from the motherboard and share a 3.3V AND ground connection to the motherboard
That is not the case. USB risers do not provide any voltage from motherboard except contol signals. Thus they are isolated.
And you are lying, they are not sharing 3.3V. They do share ground however as all devices should.
You can easily verify yourself, as I did with a multimeter, the outer pins of the USB cable connected to the motherboard have 3.3V coming from the motherboard connecting to the riser. Your confirmation that they share a ground and yet are electrically isolated shows you are clueless and I would
DEFINITELY NOT listen to your advice.