Quadlet actually solves this. It's the newer way to define containers for systemd and handles the rootless user case properly. I migrated my services to it recently and it's much more robust than the old generate scripts.
Could you give an example system-level quadlet that accepts connections on a low port, like 80, but runs the actual container as a non-root user (and plays nice with systemd, no force kill after timeout to stop, no reporting as failed for a successful stop)?
My understanding is quadlet does not solve this, and my options are calling "systemctl --user" or "--userns auto". I would love to be wrong here.
Quadlet are great but running podman via systemd as a non root user worked perfectly well before quadlets and I have no idea what your parent is talking about (I'm currently in the process of converting my home services from rootless podman over systemd to quadlet)