It's not all that hard to practice writing German; we do it in the Crossover Chat all the time. (-: The topics are usually more everyday than literary, but that can still be a good way to practice things like declining nouns, conjugating verbs, and learning idioms. You're welcome to try it out any time, though it's not set up for people to give extensive corrections on longer texts, as everyone is a volunteer.
I don't think the Bible is necessarily a bad
place to study translation issues, especially if you're already familiar with some of the texts or interested in the content for its own sake. Precisely because there are so many different translations, in English as well as German, it can be instructive to compare the ones that are best known, though scholars might caution that you don't really get the full picture until you can also study the original languages, Hebrew and Greek.
The original Luther Bible is the one listed as Luther 1545. Its language is roughly comparable to the original King James Version (KJV) of 1611, which is roughly comparable to the early modern English of Shakespeare.
There are 20th-century versions that are loosely based on those translations, with the most familiar verses kept as recognizable as possible but the rest of the language gently modernized and some translation errors corrected. So the Luther Bible of 1912* is roughly comparable to the Revised Standard Version (RSV) of 1952, in that those are the most familiar 'traditional' versions, the ones that many middle-aged to older adults grew up knowing.
There are many more modern translations. The current standard American Protestant one that you might want to bookmark for comparison is the New Revised Standard Version (NRSV) of 1989. Bible Gateway and other evangelical sites tend to feature the New International Version (NIV) of 1978, also widely used and since updated.
There are also various Catholic translations in both languages. The American ones have never been very highly regarded, but the Jerusalem Bible and its successor editions are well worth bookmarking. A well-known German one is the Einheitsübersetzung, which also exists in various versions with the most recent edition apparently being from 2016.
*I used to use a site called diebibel.de (if I even recall correctly), which seems now to have morphed into bibel-online.net; it has Luther 1912, though Bible Gateway doesn't seem to.
Or was it die-bibel.de, which still exists and has a 2017 revision of the Luther Bible? It's sponsored by the Deutsche Bibelgesellschaft, which seems to be relatively conservative and doesn't actually offer many choices.https://www.bibel-online.net/uebersetzungen/https://www.die-bibel.de/bibeln/online-bibeln/https://www.die-bibel.de/bibeln/wissen-zur-bi...https://www.bible.com/de/languages/deuhttps://www.bibleserver.com/bible/EU
Hope that helps.