MC Modpack World Loading Crash at 54%

Hope this is the right place to do this. Been having a crash on creation of a new world in a modpack I am currently in the process of creating. The crash happens on any world type. Crash report linked below. I used F3+C to force the crash, as it just freezes at 54% every single time. It is also in 1.16.5 and not 1.17, unsure as to why that is the only option when I am confident that I have seen stuff from other versions here before.

Note: Not good English, friend write script again for me.

https://pastebin.com/6YEai86k