I'm trying to put together a modpack without using curseforge by using the nesting mechanic of fabric mods but while the other 90 mods work hexcasting just breaks and won't load in, even when nested alone. I know nesting isn't really supported but I'm just curious why this mod is the only one that has problems

Not really sure what this means or why it would be necessary. There's also not much we can do without version numbers, repro steps, and a crash report. Please open a new issue with that information if this is still a problem.