I've decided to try modding TSM and I've tried basically every route (except putting it in Shared and moving the Packages file from there into it and in the Documents folder because it's not supposed to go there) but the only one that doesn't crash but leads to indefinite loading is:

Mods (and Resource file) in C:\Program Files (x86)\Origin Games\The Sims Medieval\
d3dx9_31.dll in C:\Program Files (x86)\Origin Games\The Sims Medieval\Game\Bin
I know mods are installed because Grim's Medieval Core Mod shows up on the opening loading screen and in the options menu. I really don't understand what the problem is.

I'm on Windows 10 and the only mods I have installed are:
Grim's Medieval Core
Male Maternity
Treeag's AutoDisableClothingFilter
Treeag's EditinCAS