[rerdavies]

The Raspberry Pi 4 has separate USB hubs: one for WiFi and ethernet (an internal hub), and another for external USB ports. The USB port service loop will run with higher priority, so there doesn't seem to be any serious adverse affect.

The same isn't true for SD card access, which does cause dropouts. I've seen a video that suggests that disabling power management for the SD card hardware will correct the problem -- specifically that changing power state causes a 3ms delay. But I'm not quite sure how to go about disabling that on a Raspberry Pi OS.

. WiFi doesn't seem to affect audio latency. That's not true for Raspberry Pi 3, where WiFi and USB ports do run on the same USB hub.