Try refreshing the metadata for the show.
If I choose TheTVDB(Aired) episode ordering, I also get episode titles. Edit the show (pencil icon) → Advanced → Episode ordering.
You can also Plex Dance the show.
This matched correctly on my system, pulling the correct show poster:
/tv
../Berlin 1933 (2023)
..../Season 01
....../Berlin 1933 (2023) s01e01.mkv
