I have looked over linking DLL files in your project and wondered if it is possible to use vb.net dll files in UE4 instead of C#? It wouldn’t be on a large scale but I work with VB.net a lot on business applications and have some functions that work with Windows environment that would be useful in an UE project.
From what I have read there is no difference in regards to the language used to create a .Net DLL/exe as they both end up generating the same .Net JIT ready code.
HTH