I can't test it (or you tell me how).
I deinstalled all Mixxx 2.3.3 Flatpaks on all devices and installed on all the ppa 2.4 - 1219 version.
Before i used on all devices the flatpak 2.3.3 version because the soundcard switching made at the ppa versions sometimes problems....and with the flatpak version not.
I can't test it (or you tell me how).
I deinstalled all Mixxx 2.3.3 Flatpaks on all devices and installed on all the ppa 2.4 - 1219 version.
Before i used on all devices the flatpak 2.3.3 version because the soundcard switching made at the ppa versions sometimes problems....and with the flatpak version not.