Pipewire improved its accessibility, allowing for screenreaders to start much earlier

Incorrect. Not run as root, but launched by root in a system service (runs as the pipewire user).

Hum, don't know if this is a pipewire issue or if the DeskMini has too bad shielding (then again, DAC is outside via USB-C). But each time i have slightly huge CPU load, audio starts glitching with crackling to the point of failing altogether until restart of the audio server.