[NAME] Ye Shall Find  - Are you sure your headphones have the right type of plug for the jack on the PC? Just because it fits, doesn't mean it's right. There are multiple types of plugs and jacks, like TRS and TRSS, etc. Don't know what type port the XPS 8950 has, but you might need an adapter plug for your headphones. What's set on Windows Sound screen as the selected output?  Assuming the plug/jack combo is correct, make sure Waves is loading at every boot. Then disconnect the headphones and reboot PC. At the desktop, plug in the headphones and wait... Waves should pop up and ask what you've connected. Select a suitable option from the list. Next, open the Waves control panel (icon with white W on blue in notification area of taskbar or look on Start menu). When Waves opens, click the Playback icon. Make sure the Equalizer is turned on and then scroll down the screen to Select Output Device and change it to headphones.  Now click the sound test button in lower right corner and see if headphones are working.
We purchased a new XPS 8950 in Feb 2022, and have been using it for about 6 weeks now. Other than the regular issues caused by Windows 11 (which Dell forced down our throats), our experience has been good. We've used a number of front / rear ports without issue, and have been using speakers in the monitor, external speakers connected to one of the ports in back, and via Bluetooth. All good. Yesterday I was building a Powershell script to control audio output, and for the first time, tried to plug headphones into the front 3.5mm jack. Guess what - DOA! It seems this was never tested before Dell shipped the device. We immediately tested the other ports, which seem to be fine. I spoke with Dell, and after troubleshooting, we determined the port was bad. To make matters worse, the Dell rep told me "all the peripheral ports on the system are integrated onto the motherboard", so the only way to address this, would be for a technician to come and replace the motherboard, which Dell was willing to do. We'd thought everything had been tested by Dell before shipping, and having successfully used many of the other ports / optical drive, incorrectly assumed everything was OK. Had we noticed this earlier, I'd have requested Dell to swap the device, but we've already spent considerable time configuring it to our environment, so at least for now, instead of undertaking what amounts to major surgery, adding wear and tear, etc., we've decided to live without the front 3.5mm jack. Moral of the story: This is probably obvious to most, but when purchasing a new device, conduct a thorough test of all hardware. Open the case and validate everything is as expected. Monitor operating temperature. Test all the ports before investing time configuring.
Acceptance test your new device!