Yep -- it's an IPS LCD. And based on the failure more (here's a video of it [1]) with a vertical bar dark and the whole screen blinking when large white sections are displayed, I believe it's likely a power supply problem, maybe coupled to draw from the backlight. (Localized smaller LEDs, more get turned on when things are white.)

I'd been having an issue with a vertical dark bar during wakeup for a few months, but it'd go away after the whole screen came up so I pushed off opening a case. Then one day the whole thing started having problems.

[1] https://youtu.be/JtbTQ4ldSkI