I've double checked, and all the mods I want to use are present in the server's Mods folder, but the server does not load/install those mods when started. I've tried sending the mods when the server is off, when it's on, and restarting it. I've also tried creating a new game with the mods already in the folder. What am I doing wrong?
Solution
For anyone who stumbles on this in the future, I had to add this environment variable to my wolveix container:
environment: - ROOTLESS=false
environment: - ROOTLESS=false
Which means it was a permissions issue... it's always a permissions issue /sigh.