This might be (or might not be) helpful - I didnt read the whole duscussion. But I experience CTD on P3D startup when my USB headset is plugged in. I simply connect it after startup.

Edited October 3, 20196 yr by Lazer_cz

I'll share my experience on the off chance it helps. I just had a similar issue in the past couple weeks and for some reason and it was caused by having MSI Afterburner OSD monitoring turned on. I've always used it to keep an eye on FPS and temps but all the sudden I was getting crashes at the splash screen and disabling the OSD was the fix for me. 

I do not use Envshade/Envtex anymore since I installed REX Environment Force in May, but do I remember correctly that Envtex was in the scenery.cfg file and had to be on the very top of it? Can you check that it is so?

If that is not the issue, uninstall Envshade and see if your issue is solved.

If not, read second post section F of this topic from Elaine:

Good luck!