BetterEnd is not compatible with Artifacts, as the 'Cloud in a Bottle' item causes the game to crash, and breaks the end dimension. Additionally, it disables pausing, which causes the game to crash. The Shadow Forest Biome spawns on the overworld, which should not be possible.

About shadow forest spawning in the overworld i suggest you to read the issue below yours. About game crashing, please provide crash report

I can confirm that "Cloud in a bottle" from Artifacts mod is not causing any trouble when only those 2 mods are installed, so the issue must come from somewhere else, logs may help in spotting the issue

I apologize, I do not have the crash logs anymore. Whichever mods caused the conflict corrupted the game itself, so I was forced to reinstall to get the game running again and in a daze, I forgot to save the logs. As far as I read, it was Artifacts (but you said it can't by itself so it must conflict with another mod) and potentially another End mod installed. Far as I can tell, the only other mods I have that add to the end are Quark, Progressive Bosses and Alex's mobs. I'll go through any other mods I have installed to see if they cause anything.

Closing this since no news were given for a long time. Open a new issue and provide logs if you are still experiencing crashes