For several years now, I have been making Nurose, an online multiplayer Steam game with customizable spells in my custom C# engine, it's currently playable in Early Access and should be finished in 2025. The game uses my custom (not so good) implementation of rollback netcode and is quite fun. Over 4,000 units have been sold thus far during Early Access, with a 90% positive rating on Steam.
There are many software aspects I want to write about.
One day I will write about it when I have finished actually making the game. The game has a discord for any questions related to the game.