Ai czar, border czar, health czar...

I see it mentioned all the time in the US media but also elsewhere recently, where does this come from?

Czar is historicly the title of Russian rulers. Which these people clearly aren't, so why the use of this term?

Is it some sort of right wing dogwistle?

I can't say why people are using czar specifically but people have been called the "lord of X" or "Y king" practically forever without being literal kings or lords. It's just an emphatic way to say they're seen as powerful within a given space, it's not a claim that they're literally a Russian ruler.

There’s a detailed wiki article about it here.

TLDR: it’s specific to the US and UK, has been in use for over a century, and is largely metaphorical.

And offcourse there is a wikipedia about it, tought it was something contemporary. Thanks!

The word tsar/czar originally derives from Julius Caesar, just like the German "kaiser".

But in US terms, it was popularized by FDR during WWII.

In 1942, The Washington Post reported on the "executive orders creating new czars to control various aspects of our wartime economy."[11] Positions were created for a transportation czar, a manpower czar, a production czar, a shipping czar, and a synthetic rubber czar, all to solve difficult problems in coordinating the resources necessary to fight World War II
wikipedia

Anecdotally whenever the US government appoints one I'm convinced that that program will fail.... I was young when the Drug Czar was appointed and pretty much all since them have been shit