I contacted Dell Support again, and they have sent me some older versions of Realtek Drivers. In particular: Realtek-Audio-Driver_517YN_WIN_10.0.66.187_A03. Surprisingly, the system works fine now. I will observe it for a couple of days.
A couple of months ago my internal sound card started to behave weirdly. Specifically, whenever I used my laptop for some light gaming/youtube, the sound stuttered/glitched/or just turned off. I have tried everything:  1. Reinstalling realtek auidio drivers; 2. Reinstalling Maxx audio (and deleting it whatsoever) 3. Resetting Windows. Nothing helped. Moreover, I have tried reinstalling Realtek audio drivers again and now my sound devices are not even visible in the device manager... I am not sure what to do with this problem. The chat support was fairly useless.
XPS 9720 sound issues