that's just it though, the last example is not a simple case, hence why the last example is awkward by the commenters own admission. command line tools are fine, but you need to know when to set the hammer down and pick up the chainsaw.
As far as shell scripting goes, this is hardly anything to write home about. Looks simple enough to me.
It just retains the header by printing the header first as is, and then sorting the lines after the header. It's immediately obvious how to do it to anybody who knows about head and tail.
And with Miller it's even simpler than that, still on the command line...
tail -n +2 example.csv | sort -r -k4 -t','
sort -r -k4 -t',' example.csv