The following reply in GitHub addresses your question:

>>that is more difficult to get as you'd need to install all dependencies in your home directory and prepare all the configuration files to use/point the right executables. We have nothing at the moment for bootstrapping podman and its dependencies from scratch for an unprivileged user.

The easiest would be to install it on the system, but still use the unprivileged users for running the containers.

https://github.com/containers/podman/issues/3100

I don't think this will work unless you have a range of user and group IDs allocated for your user. Those will be used for non-root in-container users.

    $ echo USERNAME:10000:65536 >> /etc/subuid
    $ echo USERNAME:10000:65536 >> /etc/subgid

Technically you don't need those if you always run your contains as a single user mapped to your real UID.

I know uid 0 in container will always map to uid outside the container (e.g. 1005), but I haven't tried e.g. uid 999 in the container to ensure it maps to uid outside of the container (again, 1005), does that work?

> I know uid 0 in container will always map to uid outside the container

I don't think that's true. Have a look at Podman's --userns=keep-id and related options.

ah yeah, I had forgot about that one specifically