Agree more practical examples but disagree this is too abstract.
I’m thinking starting at more common scenarios then jumping to container networking. Ie - Flow of a packet on a simple node, a two interface node, then namespaces, and then quirky virtual stuff.
Another example - I’d love to see how iptables actually works. Maybe how to use ebpf to implement iptables things like source/dest NAT, Masquerade, etc.