Modpack version
1.69

Can the issue be reproduced?
Absolutely.

Logs
https://paste.dimdev.org/emalokiqah.rb

Issue
Everytime I try to create a new world in Singleplayer the game crashes before it gets to finish loading up. This is on a fresh install using the Twitch launcher and default settings with 9 GBs of ram allocated.

You appear to be using outdated Java. This is often caused by Twitch defaulting to an older version than you have available. Follow these steps to update.

• Make sure you have the latest 64-bit Java installed
  https://www.java.com/en/download/manual.jsp Windows Offline (64-bit) is the one you need
• Go to the Twitch Minecraft settings
• Add -version:1.8+ to the Additional Arguments

Additionally, I recommend that you lower the RAM allocation to 8GB, unless you're using shaders or texture packs.

Java Downloads for All Operating Systems

Java manual download page. Get the latest version of the Java Runtime Environment (JRE) for Windows, Mac, Solaris, and Linux.

I have done the things you have suggested but the error still persists?

• Log
  https://paste.dimdev.org/ezaxedowah.rbsss
• Settings Screenshot
  https://i.imgur.com/26iJdC5.png

I don't seem to have this issue with Enigmatica 2 Non-Expert mode.

EDIT:
I've also tried version 1.68 and the same issue occurs.

• Log

https://paste.dimdev.org/duwuhutaba.rb

hastebin

Hmm. You've tried to generate multiple new worlds right? Have you tried reinstalling the modpack completely?

So, I have reinstalled the modpack but the issue is back with what seems to be the exact same error.
I don't think there's any useful information in the log.

• Log
  https://paste.dimdev.org/ohugimagan.rb

Could my JVM arguments be incorrect?

-d64 -server -XX:+AggressiveOpts -XX:ParallelGCThreads=6 -XX:+UseConcMarkSweepGC -XX:+UnlockExperimentalVMOptions -XX:+UseParNewGC -XX:+ExplicitGCInvokesConcurrent -XX:MaxGCPauseMillis=10 -XX:GCPauseIntervalMillis=50 -XX:+UseFastAccessorMethods -XX:+OptimizeStringConcat -XX:NewSize=84m -XX:+UseAdaptiveGCBoundary -XX:NewRatio=3 -Dfml.readTimeout=90 -Ddeployment.trace=true -Ddeployment.log=true -Ddeployment.trace.level=all -Dfml.debugNetworkHandshake=true -Dfml.badPacketCounter=10 -version:1.8+

hastebin

Yes, they absolutely could :)

Recommend arguments:

-version:1.8+ -XX:+UseG1GC -Dsun.rmi.dgc.server.gcInterval=2147483646 -XX:+UnlockExperimentalVMOptions -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M

Alright nice, I'll try them out now and I'll see if that fixes it.

Changing the JVM Arguments to the ones you listed fixed the issue!
Thank you for your help.

Awesome, no problem.