I've been fiddling with #PipeWire and WirePlumber, #Linux's latest #audio system, trying to make my sound more reliable. I'm still not a fan, but I did finally find a way to get it to (most of the time) use my built-in speaker instead of its three imaginary HDMI audio outputs.
https://shallowsky.com/blog/linux/pipewire-output-sinks.html