Docker has rootless containers, too, although I think Podman has slightly better options for unprivileged uid management.
I have not used Docker rootless, but I imagine podman has much better and more flexible network configuration as well?
On systemd, I actually do not use systemd either, hence why I said I never tried those features. It is not a hard requirement at all. Though I have not tried to use any integrations with OpenRC and podman