I’ve seen that too, and it’s eerily resembling this very thread, with some minor differences, so I’m inclined to suspect that someone let an LLM loose to write that stuff; it’s a bit too prosaic. It even copied my mistake about the race condition and the false fix for it. 
Lo and behold, it’s the first match on DDG when searching for this very topic title.
However, I’m not interested in following this blog’s steps, because I have already went down this route, and I’m not wishing to change paths this late.
One thing you have probably not tried until now is model=alc225-hp, which, fittingly enough for “Ai” “hallucinations”, doesn’t even exist.
That’s probably one of your additions, I take it.
But this definitely is the work of hdajackretask:
/etc/modprobe.d/hda-jack-retask.conf:# This file was added by the program 'hda-jack-retask'.
/etc/modprobe.d/hda-jack-retask.conf:# If you want to revert the changes made by this program, you can simply erase this file and reboot your computer.
/etc/modprobe.d/hda-jack-retask.conf:options snd-hda-intel patch=hda-jack-retask.fw,hda-jack-retask.fw,hda-jack-retask.fw,hda-jack-retask.fw
Fix it:
sudo rm /etc/modprobe.d/hda-jack-retask.conf
sudo mv /etc/modprobe.d/alsa-base.conf{.save,}
sudo update-initramfs -kall -u
That should (un)do it. Run it an reboot, with external speakers unplugged. And then go through all alsamixer-gui sliders, especially “PCM”, “Master”, “Line Out” an mute buttons for that card; toggle the mute switches at least twice for a final unmuted state.
If it still doesn’t work, you’ll at least have a sane config again, because model=hp has nothing to do with HP, the company, and everything to do with headphones, for instance.
Acutally, make that a cold boot after resetting firmware state: power down the machine, unplug the power cord and press and hold the power button for 30 seconds. Perhaps some of the firmware hackery does survive a reboot, possibly in some limbo state. If you dual boot Windows make sure to disable “Fast Startup” there too.
And before I forget this again, you should see if there’s a UEFI update for your machine. Sometimes a newer kernel touches features it didn’t even know existed yet, and all too often that exposes a latent bug in the firmware, hence the long list of kernel quirks.