Comment by Longwelwind

You might be interested by an open-source project I started a few years ago but never really finished: https://github.com/ravens-engine/core

I had the idea after developing Swords and Ravens, an online adaption of A Game of Thrones: the Board Game (2nd edition), and realizing that there was a way to make a library to allow people to create board games without having to bother with the network part.

I also wrote a blog post about it: https://longwelwind.net/blog/networking-turn-based-game/

Good luck in your project!