Adding devcontainer.json and then using DevPod with it should be pretty straight-forward for you. You can use docker-compose inside devcontainer.json if you want to reuse your existing setup.
Ok, so I’d have this installed, and then Colima, and then vscode, all on my Mac. For the app I’m working on, I’d run it all in its own docker compose setup, I’d have the source code on my Mac (?), and the dev container would house all of the extensions and language servers and linters I need for this app, but in a separate container from my compose setup, and vs code would talk to it?