I do a lot of app dev and recently looked into Uno to see what it was because I was also confused.
Uno is sort of an alternative to Xamarin.Forms aimed at windows developers that aren't happy that Xamarin.Forms uses a non-standard XAML. Uno uses UWP XAML, which is preferred by these users.
The way I like to think of the two frameworks is that Uno is a cross-platform framework that aims to align systems to the Windows way of doing things, while Xamarin.Forms is more of a "do iOS/Android" in same codebase and just happens to also support windows. There is unique value props in each framework (e.g. Uno also targets WASM and Xamarin.Forms targets Samsung Tizen).
Uno is sort of an alternative to Xamarin.Forms aimed at windows developers that aren't happy that Xamarin.Forms uses a non-standard XAML. Uno uses UWP XAML, which is preferred by these users.
The way I like to think of the two frameworks is that Uno is a cross-platform framework that aims to align systems to the Windows way of doing things, while Xamarin.Forms is more of a "do iOS/Android" in same codebase and just happens to also support windows. There is unique value props in each framework (e.g. Uno also targets WASM and Xamarin.Forms targets Samsung Tizen).
Here is a good high level of Uno: https://www.youtube.com/watch?v=fyo2BI4rn0g