I have run into a lot of similar problems writing a state management framework for Rust (wip at https://gitlab.com/samsartor/hornpipe) and at one point despaired that I would have to abandon Rust and make a whole new reactive language. But the last couple years I've got it working really nicely with weak references and software transactional memory. Every reference is `Copy + Send + Sync + 'static`. And you can mutate objects by having a transaction make a local bitwise copy, which will get atomically merged and swapped on commit. The old copy gets kept around for undo/redo purposes. I've still got a boatload of algorithmic puzzles to solve to provide all the MVP features, which will take a while because it isn't my full-time job. But the details seem technically sound.

I did write a blog post about some of my design thoughts, although it doesn't dig into the technical guts: https://samsartor.com/guis-3/