Recently the XPS 15 9570 in question just refused to start up - no noise no lights, nothing. Tried a dock and an original power brick.
Went through the classic holding down the power button, removing the battery, even as far as removing the cmos battery, nothing would even suggest there was life going to the laptop with 2 small exceptions.
When on power, one of the internal fans would wobble a bit then stop, the entire fan casing would be red hot to touch. No noise ever came from it during this time.
On the side of the laptop is the little battery indicators (there isn't one on the power button) - 5 leds. when i press the button, just the middle one lights up, nothing else, no flashing, no front indicator, just this one small white led.
is it completely bricked as expected or does this light mean something?
Please try steps in link below, hopefully it get computer up and running again.
How to Reset Real Time Clock (RTC) to recover your Dell Portable system
If the troubleshooting step above doesn't fix the computer:
Reseat Memory module (or Ram) to see if that will get computer to start normally;
How to diagnose and resolve common memory issues on a Dell Notebook PC
I had the exact same issue happen to me on the day of your post (yesterday). I was using the laptop normally on Friday evening, but when I tried to use it on Sunday morning, I suddenly got no sign of life. Like you, I also tried to remove the battery and CMOS to no avail.
When I attempt to turn on my system, nothing happens, but the motherboard gets real hot right below my SSD. None of the lights on my laptop showed any activity, though.
I don't know if it's related, but I performed a BIOS update earlier on the last day that I was able to use my PC. Same for you?