I’m curious of the hardware being used, and what the other processes running.
Pure happenstance, after my first node (VIA CPU) physical USB host controller died, I’ve used Intel processors. I have never experienced any of these audio issues. The ASL machines have one job - ASL. Any non essential task, hardware drivers are removed. Bluetooth drivers have been forcefully removed.
I’ve used both USBradio and simpleUSB. I belive let hardware do hardware work - de/encode CTCSS, RX activity.
Also, While evidently not much understood by many, QoS (HTB) is implemented on the router. VoIP traffic on 4569 or whatever port I’m using get ‘top priority.’
If it not implemented, every other audio related needs to be halted, and get QoS properly implemented at your edge router.