I'm using Mod Manager 2...
And by not working, I mean the face geometry of the mod isn't being applied... hair, skin and make-up all appear fine, but the faces are still the base game faces... my only guess at this time is I'm either missing an essential mod that isn't listed under any of the requirements... or I have a wrong version of an essential mod like the Unofficial Skyrim Special Edition Patch, but I've checked them all and they appear to be up to date.
And when it comes to which mods, I've tried several, like High Poly NPC Overhaul, Pandorable's Males 3, plus a couple other that alter Ralof's appearance (since he's the first major NPC you see clearly), but every time it's the same thing... his hair, skin and makeup can change, but the base game geometry remains unchanged.
EDIT: Okay, so I've tried adding a skin mod and took a few pictures, and... I think I might be mistaken? There does appear to be some kind of difference between each version... but man is it subtle... like, seriously, even with the pictures, the difference isn't that significant...