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iMac 19,1 Apple iMac 27-Inch (2019)
Data in alsa-info does not identify the codec model in this system
This data is no different to hardware scans for other Linux systems
Apple iMac19,1 Computers
All of the hardware scans are showing the same data for pin connections
Only one audio control for audio playback in ALSA
The only thing I can think to try is a couple of generic modprobe options for cirrus codecs
patch_cirrus.c - sound/pci/hda/patch_cirrus.c - Linux source code v5.11.6 - Bootlin Elixir Cross Referencer
try with model=imac27 first
echo 'options snd_hda_intel model=imac27' | sudo tee -a /etc/modprobe.d/alsa-imac.conf
Reboot system to make sure option is loaded and check audio function
If that does not work, change it to model=apple 
sudo sed -i 's/imac27/apple/g' /etc/modprobe.d/alsa-imac.conf
If that does not work, change it to model=auto
sudo sed -i 's/apple/auto/g' /etc/modprobe.d/alsa-imac.conf
if that does not work, remove the modprobe file
sudo rm /etc/modprobe.d/alsa-imac.conf