I guess this bug has been solved. As stated in https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/issues/776 by @rmeissn, from gnome-settings, when the headset is connected, you can switch from HSP/HFP to A2DP. Once changed this setting my headsed sounds perfectly.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1838151 Title: Poor quality audio with modern Bluetooth headsets in HSP/HFP. Missing wide band speech support (Bluetooth A2DP codecs). To manage notifications about this bug go to: https://bugs.launchpad.net/pulseaudio/+bug/1838151/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
