This may not fit along your lines of native look and feel or WYSIWYG, but here is some technology that you might want to look into:
Tauri
Tauri is still under development so it may not be suitable for you, but it allows you to create Rust-powered desktop applications using web technologies for the frontend. Instead of using Electron, which is overly resource-intensive, they use their own maintained fork of webview which is super-lightweight.
You can use any web frontend library with Tauri.
Quasar
Quasar is a very complete web GUI framework that can make it easy and fun to make UIs. They have tons of out-of-the-box components for all kinds of GUI elements and they allow you to easily design mobile optimized applications. It is built on VueJS, so you won't write Rust for the front-end design ( unfortunately ) , but it has an integration with Tauri so you are still writing your performance logic in Rust.
Even though it is JavaScript for the frontend, which I would prefer to avoid, I can't argue against the value of all of the quality components that the framework provides and their first-class developer experience.
One of Tauri's ultimate focuses is on security so that fits well with designing a cryptocurrency. I have not personally used Tauri before, but I use Quasar for my company's website and I love it. It lets me focus on my logic while it handles all of the fancy GUI stuff that people have come to expect nowadays.
Tauri doesn't compile for Anroid or iOS yet but it is coming soon according to the README.
Anyway, may not be what you are looking for, but its something I've had my eye on for a bit so I thought I'd throw it out there. 