Chosen Solution
Please help ugh. The startup chime works. I tried starting from external drive and I don’t think it worked (screen didn’t change from this static). I reset NVRAM no change. I reseated display cables, no change. Video: https://imgur.com/gallery/Mtim8BV
Sound like maybe you damaged the display its self and/or display cable on disassembly? If you can try an external display, that might be a good test. The fact that the machine chimes, means the digital portion of it seems happy (passed power on test).
