Came here via Xisuma's reference.

From the description it sort of sounded like Optifine was optional. I tried the mod with Fabric and it was not loaded because it's not a Fabric mod. My error.

Is there any chance you might be supporting a Fabric version?

No, but there is a similar mod which works on fabric:
https://www.curseforge.com/minecraft/mc-mods/entityculling