Do you know good series?
Finding language and soundtrack on Netflix is indeed tedious. In principle, you have to try out which audio tracks are available for each title of interest.
My Holo Love, My very first love and Love Alarm are to my knowledge in German. I also liked My Holo Love quite well (however, I can't stand the synchronization and prefer to watch with English subtitles, so I can't say anything about the audio quality). Quite a few animees are dubbed in German, if you are interested in something like that.
For example, Erased and The Naked Director are synchronized in English (I have never seen either).
What you can do is use filters on Flixable (https://de.flixable.com/) and search. Since audio can be put in German. Asia series in itself, I don't mean to look for, but just "international series". Then you can also sort and scroll through the rating.
The offer is more than limited, there's almost never a German soundtrack. Perhaps you are more lucky with English if that is an option for you. But that should also only be the case with a few series…
Do you know the Netflix codes? This will at least quickly get you to all Asian dramas and you can search more specifically than just through the suggestion lists. https://www.netflix-codes.com/
