World generates as an empty void.

[TheRingBearer]

I'm using the latest version of forge 1.12.2 using a modpack of my own creation.
Every time I generate the world with all mods installed, it is an endless void in all directions. Only modded structures still spawn in. 
If I use half or a quarter of the mods, it works. There is some conflict here and I can't seem to find it no matter how hard I try. 
I have never encountered a similar issue before, and I have failed to find anyone on the internet who has either. 
I went to reddit and discord first, but neither had any idea what they were talking about, or how to fix it, so here I am.
Any ideas?

Log: https://drive.google.com/file/d/1AklMb4sEhuoBZDfy2hUoIflErLK6oFfo/view?usp=sharing

[DaemonUmbra]

As you have already been told, 1.12 is no longer supported.

Stop trying to dodge that fact.