@justsoup #slint might fit the bill. Written in rust, backed by a UI toolkit company, DSL (compiled to native rust or C++ code) and support for writing your business logic in either #Rust, #C++, #JS or #python.
It scales from microcontrollers with a few KiB of RAM to Win/Mac/Linux and Android (with GUI acceleration of course).
Of course open source (GPL) with a commercial option and a royalty free license for anything not embedded.


