The origin of kaput presented by "etymologists" seems to be inconsistent and even irrational
1. A change of meaning of the Latin caput occurred in German, in which kaputt now means "wrecked" or "broken". Germanic burial squads in the Middle Ages counted each corpse as a "head", or caput, so the word came to mean "broken, wrecked, or unserviceable".
2. Capot was borrowed into English directly from French as early as the seventeenth century as a noun signifying the winning of all the tricks in piquet (a card game) and other games.
In German this same capot was transliterated as kaput, and from the sense of having lost a game, German kaput developed the senses of "finished" and "broken".
3. Informal, "finished, dead, done for, broken (of a device or machine)".
From 1895, borrowing of German kaputt, probably abstracted from the earlier phrase capot machen, a partial translation by false interpretation of faire in the French faire capot, "be defeated", from its use in the card game of piquit where the phrase refers to losing all the tricks in a game; ultimately from capot cover or bonnet, from Middle French cape cloak.