In pulseaudio I have set the file “daemon.conf” the default fragments from 2 to 4 and for now no more stuttering with mixer type on software, not even with the rotary encoder switched on.
just test it for a while and see if the problem really goes away, but for now no stuttering…finges crossed!
https://wiki.archlinux.org/title/PulseAudio#daemon.conf
default-sample-format = s16le
default-sample-rate = 44100
alternate-sample-rate = 48000
default-sample-channels = 2
default-fragments = 4
default-fragment-size-msec = 200