The "phone stuck with black screen" thing happened to me on every android phone I ever had though (and here I can't restart the x session, I have to reboot it or take off the physical battery when things go really bad), so maybe it's more of a kernel level issue ?
Yeah I was about to say I have a very similar problem with my Nokia 3.4. I can usually hold power to reboot though, which I think after long enough it does itself. Sometimes I'm only aware of it (not currently using it, certainly not heavily) because it suddenly reboots itself.
