I would not blame the Pi Zero for this What kind of source do you use for up sampling?
Using a Pi Zero (w) with a PCM5122 DAC (PIFI) it does not have issues up to sources [16 bit, 44.1 kHz, Stereo]. Above it might not make sense (if up scaling makes sense at all is a different story).
The settings in Moode are for SoX: 32/384 with high quality.
The "top" command reveals <50% CPU for the mpd, which leaves still some headroom. I cannot hear glitches.
Without SoX diabled, mpd shows about 10% CPU
Meaning, before you invest in a Raspberry 4, you might want to check your setup.
The Pi Zero actually performs very well with Moode.
BR
Using a Pi Zero (w) with a PCM5122 DAC (PIFI) it does not have issues up to sources [16 bit, 44.1 kHz, Stereo]. Above it might not make sense (if up scaling makes sense at all is a different story).
The settings in Moode are for SoX: 32/384 with high quality.
The "top" command reveals <50% CPU for the mpd, which leaves still some headroom. I cannot hear glitches.
Without SoX diabled, mpd shows about 10% CPU
Meaning, before you invest in a Raspberry 4, you might want to check your setup.
The Pi Zero actually performs very well with Moode.
BR