@stuffifound idk my trans friend says the thing with pronouns is too much. Some of her closest friends even jokingly call her by her male name. I would find at workplace and job posting gender neutral language more important like instead of actress actor "acting person". In German I have not even a clue what the gender neutral pronoun would be but at least the gender neutral occupation when every occupation has a gender in German would be great to prevent systematic discrimination at work imo.
I'm sorry for your friend to have to experience that, misgendering and moreover deadnaming are definitely signs of disrespect. Please don't be like those people. Call people how they want to be called. I don't speak German so I can't help you with that but I'm sure local queer or trans advocates can help you further