Just as a security note: being in the docker group allows root access. If your user is not already a sudoer anyway, they can get root through docker.

So if you run malicious code (like running a bad install script from the wrong github repo or installing the wrong dependency) as that user the attacker can escalate to root without knowing the user password.

(The trick is to create a container and mount /. Then you can edit whatever files you want inside of the container, like editing /etc/passwd and setting a known password for the root user)

For most "normal" setups, no. Networks, environment variables, volumes, permissions etc. map pretty much one-to-one.

If you're using compose, you can even keep your setup mostly unchanged and use podman compose. Although, I would recommend learning a bit about quadlets and using them instead. There's a tool called podlet that can help you translate your docker commands to quadlets, although it's not complete and does miss some features. The annoying thing can be some QoL tooling that exists for docker compose that doesn't for quadlets e.g. automatic restart for changed quadlet files. I wrote some scripts for most of these situations. I will probably release them at some point after I make sure that they don't rely on any specific properties of my setup. But you can easily write them for yourself if you know some shell scripting.

For docker run commands, you can mostly get away with changing it to podman run.