USB Dac Dragonfly Red - Can't get it to work on Flyme. Should I use CM13?

Hello! I’m currently using Flyme OS on my Meizu Pro 5.
An update to 5.1.6 didn’t work so far. I’ve often got the notification, downloaded the update, but it always said something was corrupted. Also manually downloaded and moved the to the correct directory.

Now to my question: Did anyone get an USB dac to work properly with flymeOS? If I connect my Dragonfly Red to the Meizu, the OS says a USB audio device is attached. I lose control over the volume, but nothing can be heard in any audio app. Also USB Audio Player Pro doesn’t detect any USB audio device. Instead, I get a notification that Linux has detected a device, but Android doesn’t. Restarting doesn’t fix anything. I also tried USB debugging from the Developer Options in Flyme, didn’t change anything.
Would installing a custom OS such as CM13 get my Dragonfly to work with the phone?
Many thanks!

A little update: I’ve used USB Host Check. Thanks to the root permission, it could change handheld_core_hardware.xml.

After a reboot, I can now use the Dragonfly Red in USB Audio Player Pro (!).

However, using other apps, the sound is played over the loudspeaker. Any ideas on this?

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