But while I did eventually get my C1, my German isn't great so I don't want to claim any expertise.
EDIT: This may be interesting for you though. https://en.wiktionary.org/wiki/Appendix:German_nouns_which_h...
https://infothek.rotkel.de/rechtschreibung/genus.html
A well-known example is "die/das Tram" (rather a Helvetism; this words means the same as in English; the more usual German word is "die Straßenbahn). In Standard German, "Tram" is considered as an abbreviation of "die Trambahn" - so it is female. In South Germany and Switzerland, "das Tram" is used.
- der/die Butter
- das/die Huhn
see e.g., https://www.spiegel.de/kultur/zwiebelfisch/zwiebelfisch-der-... (German) for more local linguistic peculiarities.
https://en.wiktionary.org/wiki/Joghurt
More examples here
https://en.wiktionary.org/wiki/Appendix:German_nouns_which_h...
It's basically different in any county and different counties can be right next to each other.