I’ve been having issues with poor audio quality on Ubuntu 21.04 with seemingly everything but the headphone jack. I attempted a USB-C → DisplayPort adapter, USB-C → HDMI, and a USB-C hub.
Ubuntu 21.04 comes with a version of pipewire that’s about a year old (0.3.24), and they’ve come out with a lot of fixes recently.
Adding the upstream pipewire PPA repo allowed me to install the newest version of pipewire:
sudo add-apt-repository ppa:pipewire-debian/pipewire-upstream
I’m still testing it, but this seems to have resolved the audio quality issues.