I think what you're looking at is: "Here's an example of installing this on ubuntu 24.04. These instructions will also work on 22.04." This is in no way saying they can only get it to work on ubuntu; they just haven't written a step-by-step example like this for other distributions.

And yeah, trying to use podman with something that's based on docker compose is ... probably gonna give you some headaches, I'd guess. I don't particularly know the pitfalls but if you're expecting it to be transparently swappable, I don't think that's an owncloud issue.