I appreciate the empathy and relative calmness on this. I want to push back on a couple things and also provide some personal perspective.
Regarding "i just really need it to not be the same noncommital-at-best term insufferable nerds have been using for decades to identify bodies that look like mine" and "impossible for me to decouple from nonqueer people using it as a porn tag because it is synonymous and rooted with all of these other forementioned fetishistic terms/slurs":
A central aspect is that the misuse of lgbtq terms is inevitable, and not only that but the demeaning fetishization of transfems is a cultural phenomena that will grab whatever it can. Any other term that becomes popular for "feminine men" will end up misused the same way because that's how transphobia and the fetishization of femininity work. I don't see how that's avoidable. Its no different than "gay" or "man" being misused at trans women, its not about the words themselves but about the fundamental existence of transphobia and fetishization. To point: The growth of femboy as a porn term directly coincides with its used as an identifying term, it is something that is grabbed as it gains notice via the gravity of fetishizing transphobia, not something that fetishizing transphobia manifests as a new weapon, but as a response to how their brains conflate different queers in a transphobic way and thus take any term that fits that mold.
Also "decades" is a really big stretch. It really seems to me that the "decades" thing is based on a misinformed false history of the term. Frankly, its borderline impossible to find any instances of the term being used before 2011. It wasnt until around 2017 or so that the term became a significant force in porn, more common in some areas(ie furry sites) but still not widely known before the term exploded in 2020. Back in like 2011 shitheads were(as far as i can research) completely unaware of the term and they still were full-hose on tr*p anyway(which has direct bad meaning inside the word, unlike femboy). At that point(2011) it had rare use in furry porn, thats all i can find, hardly a broad societal fetishization.
There's a tiny amount of evidence that it was a used as a catchall antigay/antifem insult in the 90s, otherwise its hard to argue theres evidence of it frankly even existing prior to 2010, with google trends showing literally 0 results repeatedly- a far cry compared to terms like sh*male and so on. My first encounter with it was eagle summers talking about identifying with it in in bigender terms in 2013 https://www.youtube.com/watch?v=R7WPx-y__pY , and then very rare encounters until it started becoming really noticed later on.
Whenever the discussion of the term comes up, I often see 30+ year old trans women even say that they've literally never seen the term used as a slur, which is not something you can say about any other slur- if you avoid 4chan prior to the term becoming generally known in 2020, then seems to be borderline impossible to have run into the term as a slur prior to it becoming a widely known identifying term in 2020. The internet is full of highly specific places, producing very different perspectives on the same words. I dont want to live in a culture that lets 4chan control its perspective on everything.
I might have missed things on researching this over the years, of course. Maybe you experienced it foully a lot early on outside of 4chan too- maybe a furry site i overlooked?
"Queer" has been used to insult lgbtq people something like literally 100,000 times more than femboy. Obviously people who were in spaces when it was being used badly dont have to shed their pain, but the incredibly positive infusion into "queer" says a lot about the nature of words revolving around mass experiences.
So regarding "while I don't necessarily hold it against any young people who id with it not present for its origins", its not really about age but about where someone was on the internet. My experience in these debates is predominantly seeing 16-18 year olds who had recently been on 4chan(or saw very specific tiktok vids) yelling at 30+ year old knowledgable trans women for using the term to " know their history".
Again, I frankly dont see how this phenomena wouldn't happen to literally any other identifying term. If it becomes popular, then its going to be used haphazardly the exact same way, period. There are also lingual limits to constructing alternative terms that are intuitive and so on. Even in one of the very biggest(~1000 users online at any given time) femboy discord servers, which even has a primarily transfem modding staffing and is a wonderful place, almost nobody uses alternative terms for the word even though one would think thats the most ideal space for such a thing to emerge. There are lingual reasons for that.
Also, I dont know what you mean by "noncommital-at-best term". I'm also not sure what you meant by "skin-in-the-game"- do you mean not being closeted?
Second: Personal perspective.
To be perfectly clear(not that you implied otherwise), I am not a baby queer. I dont just go "oh all these people are saying this ok ill do this." Due to being genderfluid I have rolled gender thoughts around in my head over and over and over probably more than is healthy across a decade.
Its difficult to express how relieving the term has been. I frankly did not feel well spending 7 years in queer spaces, primarily transfem heavy spaces, having an extremely hard time finding other people like me(either femboy or genderfluid) and getting understood, and feeling invisible and strange in the middle of other queers. Sure, when i have genderfluid shifts that give me experiences and perspectives that trans women have, i could relate more, but most of the time it just wasnt that. The closest alternatives to being invisible were the vaguest umbrella terms that dont communicate you, or a bunch of nonqueers who have words for you(tr*p) that just fetishize you and hurtfully lump you in with others in the process. I think this would've been easier if understanding of nonbinary people accelerated faster, but regardless.
And then finally when the term started becoming popular in 2019 onward and I found sizable spaces for it(which were good spaces, not 4channy ones), I not only got to be among a bunch of people who understand, but also other queers finally have a relatively common capacity to understand and see me. To finally feel seen among other queers. To finally work on that feeling of "something must be fucking wrong with me because i feel like the odd one out among other queers".
I look into the biggest femboy communities and I see fundamental similarities to butch communities. I see butch parallels repeated. Hrt butches, nonbinary butches, he/him(but woman-identifying, using pronouns as a tool of expression rather than identification) butches, butches headcannoning certain kinds of straight cis male characters as butch women, etc. Its like a possibility space that existed for a type of gnc woman-aligned people for over half a literal century now exists for a type of gnc man-aligned people, something that was needed. Something that not only helps people who stay in that area, but people who benefit from seeing a broader possibility space so they can comfortably try being butch or a femboy to better understand themselves before they figure things out and move elsewhere. Having the possibility space populated allows for more gateways. The term has, frankly, helped a lot of people and I have seen this over and over and over, even as it gets used sloppily by others as a sexualized term.
The word not being known before did not result in less fetishization, it just meant different terms were used for fetishization and fewer queers felt understanding and comfort.
Because of all these feelings and bonds and reliefs, I refuse to going back to not having a term. Just like how even though people get confused about "genderfluid" over and over i will take what i can get because its better than not having a decent alternative at all. Nobody has made a decent alternative for femboy, there's always some fundamental problem with any halfassed alternative term, and like I said any term that gains momentum will get misused by shitheads the same way.
I am sick of the same things you are and like your other comment points out, we agree about a lot(and share certain experiences, although I got off 4chan earlier it seems). And I definitely wish femboy had less of an aura of sexualization around it from both queers and chasertypes. I just dont see abandoning "femboy" as an action that has more gain than loss and I cant see the term different than the reclamation of "queer".
As queer possibility space opens, as visibility spreads, reaction happens as the hateful and the ignorant process that. I think trying to dodge that makes a similar mistake to respectability politics- its not about the method but the visibility itself, reactionaries and fetishizers etc will respond the same way every time.