mono using BoxBuddy (Ubuntu distrobox). Then I ran mono UnityModManager.exe. This worked and I was able to find the install location for Pathfinder (/home/booper/.local/share/Steam/steamapps/common/Pathfinder Second Adventure). Assembly installation method, installed the Mod Manager itself, and I installed Toy Box (https://www.nexusmods.com/pathfinderwrathoftherighteous/mods/8) using the manager. I received notifications in the log that all of the installs were successful. Then I ran Pathfinder, attempted to use CTRL+F10 inside a game to open the UMM interface and... nothing. The game ran fine, but no mods appeared.