Not OP, but I've found Avalonia to be pretty much a direct replacement for WinForms. I mean that both as a compliment and a deserved insult. It's not the WinForms we wanted, but it is the one we deserve.

More seriously, it has all the strengths and weaknesses of WinForms and feels about exactly as unfinished and rough as WinForms. I still have to implement custom widgets that i would have expected to be included out of the box. It's nice that it's cross-platform, though with all the rough edges that cross-platform .net still has. It really, truly feels exactly like every C# UI framework I've ever used in the last 20 years: almost good, not quite finished, and takes an amount of effort that is just unreasonable compared to any other language/framework of any age.

I've been a C# dev for most of my career. I have more fun writing UIs from scratch by drawing individual pixels in C++ than any C# UI.