Thanks a lot, but it does not work for me 
I tried as simple user or in root. Before to plug the DAC or after :- Nothing in my ears.
If i “reboot” in Utilities the sub audio system i have an output “21”. But always no sound. Or the other answer is “Failure during module initialisation”.
See : Xperia 10 III can't use Type-C headphones and Audio during call not routed to USB DAC headset (tracked).
So i’m waiting the 5.1 of Sailfish OS 