Okay a simple idea, feel free to ignore this, but I was watching minecraft multiplayer and later, don't starve together, so I was thinking, why not have a mod that connects minecraft to the steam network? It could sync up your username, but there would be a huge problem with this, like having a non-steam game being used on steam. The solutions are: either make a central network for creating the mod, or ask permission from mojang/steam, I mean, I might get hate for this, but think of how easy it would be to play together with friends on a custom made world that is not on a cluttered server. I can't do it since im just a simple peasant among minecraft who is looking for an easier way to play with friends without spending too much cash on a server. I would be very thankful if some people took their time to read this, although probably not helpful at all, but an idea that could help everybody
1. The Steamworks API is written in C/C++ where as Minecraft is written in Java, leaving us with the Steam Web API
2. The Steam Web API can only be used to log into a players account and get certain details like their username and inventory
3. Creating a Steam network clone would be pretty expensive and someone needs to pay to support that network
Its an interesting idea however its just not feasible. It would be much simpler to just port forward and host a server on your computer or buy a cheap PC and use it as a server for you and your friends.