Rust is a great and fabulous language, but flexible it is not. If I were starting a Lemmy or Kbin type project from scratch I'd likely start with Python, TypeScript, Lua, or Go depending on what specifically I was worried about bogging me down in the future. And then later on if there were really heavy procedures or db calls that couldn't be simplified anyway else, do those in rust. I think Rust has some very interesting features for micro service development, but for a monolith like Lemmy, it's surely a nightmare