I described the full process here [1]. The only thing that seems to differ is podman for you.
Ah, I see:
> 4) As root, installed podman
I installed docker as the non-root user. See my Mastodon post, there's a specific procedure to install Docker in a user namespace ("devel" in your case).
1) Created a new LXC.
2) As root, I created a new user "devel"
3) For the "devel" user set both subuid and subgid to devel:100000:65536
4) As root, installed podman
5) In another SSH session, logged in as "devel" and ran "podman version"
Same error as before. This is in a Debian 12 LXC running on Proxmox.