I repeat: Hereditary/Family dictatorships do NOT count as monarchies, so they can exist. The head of states of these states do NOT have a monarchical title so they're fine.
Also I see a lot of very late PODs, but I'm giving everyone the freedom to choose whatever POD(s) from the beginning of human civilization until now.
Yeah, but
imperator started out as a military role,
princeps meant first (among equals), and
dux [duke, doge] meant leader, all to emphasize the pretense that the Early Roman Empire (and the Italian city states 1200 years later) was still a republic and 'totally not a monarchy'. These titles eventually evolved into title of a monarch a few generations after the position became hereditary.
Historians 500 years from now may argue that the Kim Dynasty is a monarchy, just like most of today's historians mostly consider the Roman Julian Dynasty a monarchy instead of a military leader ruling a republic.
Then you have Poland-Lithuania, which was ruled by an elected king, but practically functioned like a republic at its tail-end of existence before the Partitions.
Thus, I think monarchy should be defined by role instead of title. Otherwise, this opens up a can of worms, like Elizabeth Windsor simply abdicating and calling herself 'Lord Protector for Life', and argue that she rules a republic.