My HTC 10 killed itself, what happened ?

Hello !

I have an HTC 10. I removed my operator's ROM and installed something from xda (can't remember which ROM I was using, but it was a serious one, not a weird unstable ROM). It worked well for a long time (I would say over 6 months), but yesterday the phone froze: No actions at all when pressing the buttons, the clock at the top right wasn't updating, but the wifi indicator was animated.

I forced the shutdown by pressing power + volume down, and now it doesn't start at all. No light when charging and it was detected by Windows as a "QHSUSB_bulk" first, and now it's a "Qualcomm HS-USB QDLoader 9008".

The phone was rooted but it was S-ON, and I was on Reddit when it crashed, I wasn't updating or flashing anything.

I'm going to send it for RMA, but I want to know: what happened ? Do you think it's an hardware issue ?