Start with simple troubleshooting: Plug a pair of wired 3.5 mm headphones and see if it works.  If not please open Task manager > Startup > Wavemaxx: If it's disabled enable it and reboot.  If still no go: Reinstall the following driver: Reboot required.    [URL]  
I have a soundbar plugged into the Headphone jack on my Dell XPS15.  I have used it this way for a couple years with no issues.  No this headphone jack simply does not show up.  I'm able to select either the speaker in my monitor via HDMI or the internal speakers.  Yet that is all that's recognized. I even thought maybe there's an issue with the soundbar or the cable but I switched the soundbar along with the same cable to my other computer and it works fine, no issues at all. Is there any reason I'm unable to select the headphone jack or that it's not even showing up?  I'm using Windows 11.  
No longer recognizing headphone jack