The one big reason I dread giving up compose files is that they're a great way to have system agnostic documentation on how to setup a new stack. That means every developer can just start the thing locally, and it's pretty much the same as on the server (and everyone elses laptop).

Podman doesn't officially support any thing platform agnostic. How do you (or anyone) deal with this for a project in active development?

podman can work with kube files, which is the YAML format from Kubernetes. That's more "platform agnostic" than docker-compose. And it can be read as a documentation in the same way.