okay so... surprisingly yes, I think it works. You have to load this over Terralith but as far as I can tell the terrain is generating the way it's supposed to, with the kind of smooth slopes this datapack adds. If you load Terralith over this though it doesn't work and only generates Terralith terrain.

It actually looks quite beautiful, I'd encourage everyone to give it a try

(edit: tested with the datapack version of Terralith, for those wondering, no idea about the mod)

Ok, thanks