The "king" meaning of this name certainly fits to my imagination--I picture a very powerful and influential man. It might sound a little odd on a child, but I'm not stopping you if you want to name your son this.
Zoltan is a Slavic name. It comes from the Slavic name Zlatan (golden) but through Church Slavonic since in the middle ages gold was written as 'zoloto' which comes from the word for yellow (zolto). Some Slavic languages still call it like that. The name is basically an adjective meaning "he who is golden (ie precious)". There are at least 40 male and female Slavic names with the stem 'zlato'. This is the first time someone has derived this "Hungarian" name from Turkish. Everywhere else it states that the name is Slavic.
When you see a Hungarian name which is categorized as of "Turkic (not Turkish!) origin" it means it's a Scythian/Hun name. This name isn't of Slavic origin, it's an old Hungarian name.This name and the title of 'sultan' share a common "ancestor", but its use in Hungary goes back further: Grand Prince Zoltán/Zolta(Árpád's son) reigned from 907 to 947 AD, while the Turkish rulers took to using Sultan in 1473 (replacing the older title of Emir).
Zoltan Karpathy, Hungarian linguist in the musical My Fair Lady (not present in original play Pygmalion). (He takes Eliza Doolittle for a Hungarian princess.)
https://cs.m.wiktionary.org/wiki/Zolt%C3%A1n https://cs.m.wikipedia.org/wiki/Zolt%C3%A1n