External speakers / headphones not detected

No headphone detection. Plugging in good headphones does absolutely nothing. Speaker icon in taskbar shows only integrated speaker option, so cannot toggle to headphones. THE ODDEST PART: If headphones (or even a dummy plug like an audio extension cable) is plugged in while laptop is off, after it boots "headphones" is selectable! Can then toggle between speakers and headphone and back again and audio output works both ways. Unplug the headphones and plug back in, option is gone! No detection. Workaround is to always keep the audio extension plugged in. Rather not!  Any clues would be much appreciated.

Precision 3561 laptop. Win 10 Pro 22H2. Fully updated from Windows Update and all current Dell drivers. MaxxAudioPro (from Dell) installed. No related options in BIOS.  Thank you for any clues you may have for me.