I have tried it now a few times. It worked with 2 animes on first try. All the other ones still don't get the episode names. And the one Animes only gets the Anime Name in japanese like in the pictures above.
AFAIK, AniDB should be providing your language preference. However, I do not know how it will handle situations where there is no episode names available for your language.
I setup a test library with German as the language and region and it pulled down German episode names from AniDB for the handful of Anime I tested with.
Jellyfin 10.10.7 (Docker)
Ubuntu 24.04.2 LTS w/HWE
Intel i3 12100
Intel Arc A380
OS drive - SK Hynix P41 1TB
Storage
4x WD Red Pro 6TB CMR in RAIDZ1
I really don't know where the problem with my server is. The problem with no names occurs more often and when I use identity and use another source and say replacing image the image doesn't change and the rest is the same too.