I agree that it would be very useful to stop replacing 'zijn' altogether in the Dutch translations, so we can use the very common verb 'zijn' again in the translations, instead of working around it all the time.
A genuinely neutral pronoun instead of 'zijn/haar' would be nice, but choosing 'die/hen/hun' and automatically replacing this word, would still be just as problematic in Dutch, because all of those words also have a different meaning in a different context.
In general, I think the best option would be to use a ${thing} and replace it with the user's preferred pronoun.
A genuinely neutral pronoun instead of 'zijn/haar' would be nice, but choosing 'die/hen/hun' and automatically replacing this word, would still be just as problematic in Dutch, because all of those words also have a different meaning in a different context.
In general, I think the best option would be to use a ${thing} and replace it with the user's preferred pronoun.