All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah and that Muhammad, ﷺ, is His slave and Messenger.
We do not have knowledge of any trustworthy translations of Ibn Kathir or other books of tafsir, neither in the English language nor in the German language. There is no doubt that explaining the Speech of Allah is a matter of great importance and gravity, and thus only those translators should be relied upon whose 'aqidah, knowledge, and trustworthiness are established, and who is competent in the target language. Hence, we advise you to read and rely only on those translators who are reliable and specialists in Islamic studies.
Allah Knows best.