I find that a lot of libraries tend to be Linux-focused and generally kind of ugly on Windows, so what do you use when you want to make something that looks nice and performs well on Windows?

The best looking ones I've seen were web frontends like in Tauri. A runner up would maybe be iced-rs. Which is a shame because I really wanted to use relm or fltk-rs but it looks like I'd almost have to use the web renderer to get "sleek, sexy" GUIs...