Invalid Libraries for MonoGame

I’ve been trying to set up FMOD for MonoGame, but the dlls fmod.dll and fmodstudio.dll both are invalid.

When trying to reference from Visual Studio: “The reference is invalid or unsupported”.
When loading with NativeLibrary.Load, it throws a BadImageFormatException.

Both share a common issue - usually, it means loading an incompatible bit depth (i.e. 32bit on a 64bit machine), but that’d imply that the 64bit dll is actually 32bit. I cannot find any other reasons for this issue and it’s completely stopping me from starting to use FMOD at all.