As someone who comes from cis-centric feminism, we have kind of a different view of the masculinity in language?
We know that -er/etc is considered masculine and -ster/etc are considered feminine, but we view it as men creating a language where you *have to tell people explicitly if someone is a woman*, to point out that she is Other and Different and Lesser, as an act of shutting women out of neutral language, and therefore we actively fight being called things like maid, hostess, actress, etc, because we don't want to have our gender pointed out as relevant to our work or ability. To us feminine language exists as an act of othering, not as a natural "opposite" of "masculine" language, and we have fought to get rid of this othering categorization by making sure that -er/etc will no longer be only for men but have room for everyone, no more questioning of women including themselves in the "default".
Men have always gotten the relaxed and neutral for themselves; the permission not to shave or dress up to be an object to gaze upon, the inclusion in society without question, power handed to them instead of taken, the simple default endings to words. The dressing up of femininity that extends to language -tress, -ster, -ette, often denoting a belonging to the male counterpart like a duchess being the wife of a duke instead of the female equivalent of a duke, the othering and objectification, that is something we try to get rid of. We try to take up the neutral space we're barred from.
If someone called me a translatress or translatester or something I would feel as if they are trying to other me from my occupation and unnecessarily pointing out my gender, and I instinctively feel on guard, because gendering as feminine is not actually about identity but about othering
In a world with only women I imagine it would not exist, because there would be no reason to other, but I also imagine that masculine words wouldn't exist, all endings would just be neutral, unless they other people based on some other factor. Maybe there'd be class based grammatical othering?
Also I am not writing this as an attack, I think your ideas are interesting, it just makes me feel very complicated feelings when it looks from my perspective like people are trying to undo the work we've been doing to include women in the default and neutral, seemingly leaning into the idea that othering language is unproblematic and neutral in itself. But I know that that is probably not what you as a feminist is trying to do so it'd be best to open my mind and close the gap between us
I fundamentally don't view being a woman and the highlighting of womanhood as degrading or othering and have a firm opposition to the strain of feminism that seeks to more or less abolish womanhood as a means of evading misogyny. It's throwing the baby out with the bathwater and I take the stance that womanhood must be more firmly asserted rather than further obscured.
I've been reading Ursula K Le Guin lately, who uses "man" and "he" as gender-neutral, which was grammatically correct and the proper way to write at the time. And that's the logical endpoint of erasing feminine language to not be othered, we may as well just all call each other he, the way so many say "man" and "guys" and "dude" and so on and call it neutrality.
Even with truly neutral language that isn't just using masculine language universally, I dislike it because for the majority, neutral automatically translates into masculine. It's why there was a push towards using she universally a while back in writing, so that at the very least the audience reading has to remember women exist, and why I think universal they is a step back.
I do totally get where you're coming from, and understand that hypervigilance towards any acknowledgement of womanhood because it so often comes bundled with attack. But when I see women hide their first and middle names on writing behind initials or a neutral title so that an audience won't realize they're women and devalue their writing, that breaks my heart shows me how necessary openly fighting misogyny is, rather than compelling me to hiding my womanhood similarly.