I'm curious why in all backup tutorials I found tar command excludes among others
and not all of
Why would I want to backup anything under dev?
There is generally no need to backup anything under dev, since it's mostly generated upon boot by udev. I did a lot of OS migrations by simply rsyncing everything except stuff like proc, dev, sys etc.
Just make sure when you setup your backups, ALWAYS test a recovery, to see if everything is functioning properly.