[PROBLEM] Audio glitches (dropouts, clicks and pops) using USB DAC plugged to Pi Zero W

[pardon]

I don't have a Micro-SD card to try for a swap at the moment, will get one later today.

But! When setting Moode to AP mode, I get almost no drop-outs, like one every ten minutes instead of one every minute.
Could it be Wifi interference?

EDIT: When using Moode in AP mode, uploading a file to the SD cards through Samba makes the audio glitch every ten seconds (while the file was uploading)
Playing back a file that's 24bit 92Khz does not affect the number of dropouts. Once the file was on the SD and playing, I only got one dropout every five to ten minutes.

So it's either a SD problem or WiFi activity interfering with the USB Audio output, right?

EDIT once again: Since switching to AP mode, drop-outs have been reduced to one every five minutes (almost exactly five minutes). Connecting through SSH also gives me a drop-out.
My Pi is plugged in the Anker Powerbank, so it definitely rules out the possibility that it could come from power-related issues.

[pardon]

I tried another SD card, a fresh new one with a Moode clean install. Still pops and crackles...

I don't know if my mind is playing tricks on me, but the first SD card has less pops and crackles than the new one, with the exact same setup. How can that be?
I set the audio buffer to the maximum setting and updated to MPD 22.0 – could that have any kind of effect?

[DRONE7]

From the MoOde menu post the output from 'System Info'

What kernel have you selected 32 or 64 bit ?

From a previous post...

Install MoOde to it and replace the existing sd-card in the Pi. Load a few Flac files of varying resolutions, put them on repeat and see if you get glitches.

not your '.m4abcdefghijklmnopqrstuvwxyz' files but Flac files  
 
We're trying to find a baseline that works then add in other variables to see what the trigger is...then debug.