Headphones have no application output, only system audio

No. I mean within the settings of any particular application. There is no example to give, as it depends on the application. As I said, sometimes outputs may need to also be configured on whatever application you use.

At a system level, settings will also vary from one DE to another.

In any case, a little housekeeping…

As a new user, please take some time to familiarise yourself with Forum requirements; in particular, the many ways to use the forum to your benefit. To that end, some or all these links will be invaluable.

Please read through them, as they will help you understand the types of information that you should provide (logs, system details, etc) in order to have others help effectively.

And last, but not least, the Stable Update Announcements, which you should check frequently for important update related information. Occasionally an issue might be directly related to a particular update; it’s always best to check those announcements.

I hope this helps. Cheers.