Keepass is made with .NET. It’s native for Windows. It works with other OS using Mono, but it’s not as native, I guess.

KeepassXC written with C++ and crossplatform GUI, so it’s better fit with Linux and macOS. Also, AFAIK, KeepassXC has more features.

I’m using Keepass because I trust C# more than I trust C++ when it comes to security. But it’s nice to have options.