People seem to be misunderstanding your question. It doesn’t sound like you are lacking educational resources to learn C# but a lack of reasons. It sounds like you have been learning by getting you’re hands dirty with foss software.

C# is a sort of “enterprise-grade language” like Java. It’s meant for large applications developed by one or more teams for almost exclusively commercial purposes. If you want to learn it, deeply, you’ll have to come up with an excuse to write in it. A game is probably the best choice for this. Then learning c# is learning how to make your game.

If you’re looking for open source C# software to hack on you can try anything from the *arr stack. (Sonarr, radarr, lidarr).

The article title is poorly written but the conclusion is pretty sound: If you’re planning on writing unsafe code, use a language meant for unsafe code. Zig is meant for unsafe code, Rust isn’t.