Minecraft World Creation Problems

I wanted to ask if anyone knew about an issue involving the Minecraft world loading. I made a mod that until a few days ago was working great but recently, has been struggling more and more to create new worlds. When it starts loading the new world, it usually stops at one of the percentages from 0%-100%. I assume that this could be because of a lack of RAM but if so, I'm not sure how to fix that. The mod has quite a few mobs, only a few of which spawn in the overworld, has three new biomes and only one new dimension. Does anyone know any solutions on how to fix this issue, whether it be by removing features or something else. Thank you for your time.