I've been working on an open source game backend for Unity and Godot: https://trytalo.com. GitHub: https://github.com/talodev.

I'm aiming to solve the problem of wanting to build a game but having to build all these extra "other" systems around it (leaderboards, stats/analytics, saving and loading game state).

Right now you can drop Talo into your game for player management, authentication, leaderboards, analytics, game saves and player segmentation. There's a dashboard too so you can visualise all of your game's data.