Ubuntu had a general crackling issue introduced last year, an issue around a buffer size which I fixed by copying

/usr/share/pipewire/pipewire-pulse.conf

To ~/.config/pipewire

Uncomment

pulse.min.quantum = 128/48000

And increase to 512/48000. Restart.

systemctl --user restart wireplumber pipewire pipewire-pulse

Increase buffer until stuttering ends. Note this also introduces delay to audio.

Perhaps your issue is something similar? I wouldn’t blindly make these changes on your end, but maybe it’s something to search up on.

Calibre is better installed by its own method as outlined on its site. Any apt repositories are unofficial and likely to be behind current.