WindowServer Crash in Sierra/HS

Dealing with sudden freezes that randomly happened two nights ago using Sierra. There's no rhyme or reason to them although it does not seem to crash in safe mode. Usually happens at login or just after login. I'm using a late '13 MBP

What I think— after two days of troubleshooting— is its a WindowServer Crash error. I've completely obliterated my SSD twice, even wiped the recover and updated via Netboot.

There are a lot of these issues out there that I can see, but only one positive result posted by (I think) Linc Davis. The link he gave is obsolete so it doesn't help me.

Hardware tests/diags are all 👍 but finally opened up Console and went through the system logs. I don't have a log of the error as I cleared them trying to hone it on the freeze, but EtreCheck confirms it.

The one instance I can find of WindowServer acting up in Console is:

WindowServer [ERROR] - Unknown CGXDisplayDevice: 0x41dc9d00

Etre's diagnostic log:

Diagnostics Information:ⓘ

2017-09-21 13:46:59 Last shutdown cause: 3 - Hard shutdown

2017-09-21 13:24:50 WindowServer Crash [Open]

Cause: StartTime:2017-09-21 13:24:17

GPU:IG

MetalDevice for accelerator(0x3623): 0x7fe66fe360e8 (MTLDevice: 0x7fe670832200)

IOService:/AppleACPIPlatformExpert/PCI0@0/AppleACPIPCI/IGPU@2/AppleIntelFramebuf fer@0

Assertion failed: (false && "10 seconds of continuous GPU Driver unreadiness, relaunching WindowServer"), function IMGGraphicsStackReadinessFailure, file /BuildRoot/Library/Caches/com.apple.xbs/Sources/SkyLight/SkyLight-312/SkyLight/ Server/Windows/Updater.cc, line 3052.

If you can help, I will literally send a six pack of the beer of your choice or a giant burrito.