I created a recent project: ZypherLink. This project is a multiplayer framework to make developers not think that creating a multiplayer game is very difficult, very expensive and without doing crazy things with Unity or other libs that you don't know what are doing with your project.
This project is fully open-source, and uses WebSocket(TCP) connection. And is very easy to modify, and with ZeroPing, the Unity Example Project you can see how works!
This asset I will do because doing a think like this if you know about JS and backend is too easy to do.
The link of project: https://github.com/superstrellaa/ZypherLink and it's in itch.io: https://superstrellayt.itch.io/zeroping