Unreal is open, but where i can find code of this game? And i know, that create multiplayer isn`t easy, but my team have a lot of times and ready to work :D
Isn't .pak file in VotV\Content\Paks already contains all scripts?
Also, this game has a page on thunderstore with mod loader and some other mods: https://thunderstore.io/c/voices-of-the-void/, I didn't test any of them yet but I think you can use UE Blueprints for modding the game