Thanks - that's really interesting, in a weird-interesting way.

I'm far from an expert in such things, but I'd observed that the approach in English to gendered words (actor vs. actress) seemed to be, over time, to drift towards calling everyone an actor - as a neutral term, to avoid treating women differently, rather than a male term per se.

In German, from your explanation, it's gone the opposite way - aggressively maintaining the female option because of a dislike of broad adoption of the male version as a neutral default.

It's not "aggressively maintaining the female option", it's just a language quirk. English has a gender-neutral "the" article which you put in front of every noun, German has three different variations of "the" depending on the gender (der/die/das). Literally every noun has a gender, including inanimate objects such as a piece of furniture. "The table" is always masculine ("der Tisch"), "the lamp" is always feminine ("die Lampe") and "the bed" is always neutral ("das Bett"). Sometimes changing the article completely changes the meaning of the word, for example "der See" is the lake, but "die See" can be the sea or the ocean.

Only living things can have more than one gender and in that case, not only does the article change, but so does the suffix. There is no "singress" in English, only "singer", but in German there's "der Sänger" or "die Sängerin". Calling a female singer "der Sänger" would be grammatically-speaking completely incorrect.

The only thing that changed fairly recently is that more and more people intentionally try to maintain gender ambiguity when they don't intent to specify a gender, in which case "the singer" becomes "die Sänger:in", or even "der:die Sänger:in" if you want to be even more pedantic.