The letter ‘z’ seems to freak out native English speaking learners of German. Many develop an impression that it’s different and foreign and hard and therefore give up on it quickly. But mispronunciation of a common consonant is one of those clues a native speaker will pick up on immediately that you perhaps need them to switch to English on your behalf. Even if that’s not true.
Giving up early on the ‘z’ is a shame. The sound itself is one that we native English speakers use frequently — just not word-initially, like it can occur in German.
Here’s where you use it in English:
…just to name a few proper nouns. A few of those seem Russian in origin (Trotsky, Yeltsin) — maybe the acceptable pronunciation of Czar (though we prefer Tsar) has wrought havoc on Americans’ confidence in pronunciation of German word-initial Z sounds.