I used cloud9 about ten years ago and it worked well. Think it was in Michael Hartl’s rails book - was bummed when the site was purchased/changed and whatnot. Don’t use one anymore or since
I tried Codespaces but one day my internet connection was bad and I couldn't do any work. I've switched back to local dev
I use remote development environment on my VPS using code-server ( https://github.com/coder/code-server ). It is quite easy to setup.