You might also want to look into Dioxus Native as it's doing a lot of what you're interested in too, with taffy and vello for example. The gaps I see in the Rust UI ecosystem as you asked are that I want a true cross platform solution for mobile, web, and desktop while most focus only on desktop, as I use Flutter currently for this purpose but need to pull in Rust crates through an FFI layer like flutter_rust_bridge, as well as a backend server in Rust and having to share types with the frontend through some agnostic format like GraphQL, so it'd be nice to have everything in one language. Dioxus Native does in fact bill itself as "Flutter but in Rust" which I'm looking forward to a lot.
How was it like working at Zed? Any reason for leaving?