New M1 Mac mini - No audio on USB after sleep The problem
I have a new M1 Mac mini connected to a Philips monitor, connected via the Thunderbolt (USB C) port.  Whenever the Mac wakes from sleep, the audio is not working and is fixed by toggling the following setting: Audio Midi Setup &gt; Format
I can see that there is an error, but there's no tooltip to explain what it is.

Hardware
Mac
Mac mini M1 with 16Gb and Mac OS 11.1
Monitor
Philips 499P9 with a built-in docking station, featuring:

Audio
Ethernet (which appears as USB Ethernet in Network settings, but won't connect)
Multiple HDMI and USB C inputs
USB B connector for HDMI 1 device
Multiple USB A ports for shared peripherals (keyboard, mouse, headsets, etc.)
The Exclamation mark in a speech bubble is not an indication of an error, but shows which audio output is configured for system alerts and sound effects.
Having said that, I've experienced problems with external audio after sleep on my 2018 Mini. I suspect it's a bug. I have to kill the coreaudiod process to get things working again.
sudo killall coreaudiod

Then enter an admin password.
If you are changing the Sample rate to get things working, then it may be that doing that restarts coreaudiod. (Assuming it's the same issue.)
Note that some audio apps may crash or get confused if you change the sample rate while they are running.