Disagree,
There are so many changes with containers and the ecosystem around that aspect its really challenging to find someone who really understand the lower levels of linux.
Compare Slackware to Ubuntu. Ubuntu has all the new bells and whistles where Slackware remains loyal to its roots. I think you can learn more with Slackware and many of the choices Ubuntu is making will seem questionable to you.
That said you will need to learn Ubuntu and the new container ecosystem.
Networking is something I see many many people simply do not understand. NAT is a hack that has infected everything and there are layers upon layers of it causing issues everywhere.