Felt like sharing this here because I've no friends.
For reasons, I decided to get back to TTW, and with a fresh install. So, I re-install NV, get fresh TTW installation files and updates, and browse for mods while it's installing.
Everything goes well. I install everything without a problem, including the mods, and hit the NVSE button on MO2. It doesn't work.
"Derp", I think, and run NV manually, starting with the launcher and then the NVSE.exe file. Everything should be good now, I think. Well, the game runs. Without the mods, obviously, since they're done with MO. But launching NVSE through MO still does nothing.
I look around, re-check mods for (in)compatibility, even browse discord. I try all the usual things, disabling and uninstalling the various mods, etc., nothing works.
..until I run the hecking NV launcher through MO2. And I only did that because I was too lazy to open the NV installation folder again.
*facepalm*
Why on earth I didn't think of that at all, with my 10+ years of modding experience, I'll never know.