In case it helps, Render (https://render.com) has first class support for Rust webapp hosting without needing Docker.

And here's the Hello World URL for this tutorial! https://rust-nix-helloworld.onrender.com/hostinfo

More info at https://render.com/docs/deploy-rocket-rust. I'm the founder; happy to answer questions here or in our user chat at https://render.com/chat.