Allo Aternos Team!
Is there any chance you could add the mod "InstantUnify" as a mod option?
Link to the mod: https://minecraft.curseforge.com/projects/instantunify
Instant Unify is a simple mod that has zero dependencies. It automatically unifies dropped items and any items in your inventory into a single copy of that item according to the OreDictionary. It has support for mods such as Unidict, using them as it's governor if possible to smooth out gameplay and ensure everyone's inventories are tidy and resource-packs aren't broken! It's had 575 000 downloads as of it's most recent version as of 6/1/2019, and I think it'd be worth looking into!
Thanks for reading!