I run both Fedora and Bazzite on my Steam Deck (LCD) in dual boot. Since upgrading to Fedora 43, I could no longer get the audio on the built-in speakers to work. It was still working on Bazzite.
After diving into it, I managed to fix it. Here's how, in case it's useful to anyone else.
I used the ALSA / ucm2 config from Valve's repository for audio processing for their hardware: https://github.com/evlaV/valve-hardware-audio-processing
Try:
git clone https://github.com/evlaV/valve-hardware-audio-processing.git
sudo cp valve-hardware-audio-processing/ucm2/conf.d/acp5x/* /usr/share/alsa/ucm2/conf.d/acp5x/
sudo mv /usr/share/alsa/ucm2/conf.d/acp5x/Valve-Jupyter-1.conf /root/
Note this is for the Steam Deck LCD version (you can check that cat /sys/devices/virtual/dmi/id/product_name gives Jupiter). The repository also contains configuration for the OLED version, but the commands may be different.
Hope it helps anyone!
Indeed. PC manufacturers should just invest in the Linux ecosystem.