I am currently having the same problem. I have narrowed it down to being a problem with enb.
With all mods completely removed, and only having enb, this happens.
Remove enb and no problems.
Install all mods again and still no problems as long as I don't put the d3d9.dll back in the skyrim directory.
I have found that if i have the mod that removes fog from the main menu, it will launch the game. However, when I try loading or creating a new game it is an instant crash after the loading screen. Then same as before, if I remove the enb .dll it loads fine.
I have uninstalled and reinstalled the enb files multiple times to no avail. I even tried going back and forth between .119 and .122, but nothing works.
I want enb to work, but no idea what to try next.