German enhanced Anna voice under Voiceover totally lost since IOS 18

I know, this issue affects maybe a very small ammount of folks in the community, but it would be very helpful, if I could get a good advice for our problem.
Well, my first iPhone was the iPhone 4S and since then, i used the enhanced Anna voice under Voiceover which is a German voice.
In the following years, some pronouncing adjustments has been done to improve the pronouncing quality and the voice quality in general. I get very well with the Anna voice and had no issues til IOS 18 was released.
Anna's pronounciation has been totally changed into negative! The pronounciation of times, easy German words or even simple letters has been totally changed.
Words which are German, get now prounced as there're English or French words. The number 10 is now prounced as X, like the Roman number.
Since then, it's very strange to do simple tasks with your phone, because everything sound so different and often very wrong.
I want to report this issue to Apple's Accessibility team but I've one question: does Apple have influence over these voices and it's pronounciation, or did they purchase them and another company are setting them up?