alt Hacker News"C# Markup" [1] [2] sounds a lot like what you are looking for. As the only "second party" option in this space it's interesting that it is so MAUI only/MAUI focused, but I suppose that's the "new hotness".
There have been similar F# libraries and third-party C# libraries for a while that seem nice to work with in similar ways.
[1] https://learn.microsoft.com/en-us/windows/apps/windows-dotne...