Thanks for your feedback.
I contacted DeepL about a similar issue, and although I haven’t received any formal acknowledgment, it seems to me that that issue has been fixed, so I’m wondering if the text you tried with is now properly formatted too? When I try the text, this is what I’m now getting:
I don’t read German, so I’m not sure if this is better, but at least there is a space after the period and the sentence begins with a capital letter.
And thanks for letting me know about the dummy key. Actually, I’ve been aware of this for at least a year, and was a bit surprised that nobody took advantage of it…