I've really been ignoring the roles of men in this setting, in much the same way that most settings ignore the roles of women. It seems that in virtually every story where there are "Amazons" or systematic upheavals where the men are all but annihilated and the women have the power, we see the society of the story depicted through the eyes of a male protagonist. In these stories, the male protagonist seems to invariably come up with the question "But who does the man's job?", this is considered incredible poignant....the first time. The second time the question is raised (in some other story) it might also make the audience think, but it's basically become a trope in this type of setting.
There are no men's jobs, there are no women's jobs. There are only jobs that you have been socialised into believing are gendered.
In this setting, men are weakened. They have value as sperm donors, women gain prestige for hiving kept one alive beyond a certain age, they are fragile things who maintain their value by looking pretty, but as soon as they have cracks in their visage their worth dwindles quickly, and in most cases a few scars mark a close temporal proximity to the end of their life. Men are forced to be social, because being physical is dangerous for them.
There is no real hard science here, it's quasi-mystic. Biologically there is a level of handwavium infusing the background. From the perspective of fungal strength and weakness, the notion of male and female is specifically defined in a biological sense (XX and XY chromosomes), but it leaves inherent messiness when dealing with those individuals who might straddle the biological divide, whether hermaphrodites, XXY chromosomal individuals, or other genetic configurations. I could specifically link the effect to testosterone levels, but this ends up just as problematic. The hard science will always have holes, so I fully admit that there is a glossing-over of the finer details.
Bringing the testosterone element into play, we might see a caste of eunuchs; such men might have been boys who showed potential or a natural aptitude at a young age. As a result of surgical body modification, a boy gives up the ability to contribute to the next generation of the gene pool, but they do not suffer the debilitating weakness that afflicts other adult males (on the other hand they don't gain the advanced regeneration of the women). Such men are considered half citizens, they were chosen to become eunuchs for their potential, and they are allowed to contribute to society because they show continued aptitude. As specialists in a specific field, they are respected, but outside that field they are considered barely more than adequate... they are still relatively fragile (even though they do heal slowly), and they will never pass their genetic heritage on to the future. Some cultures might see eunuchs as a valuable commodity, others might view them as a useful way to ensure knowledgeable men have a place in society, and some might consider the whole practice a barbaric superstition or abomination.
Of course, sex and gender are two different measurements of a person's identity. For the purposes of discussion here, sex is the biological configuration of an individual, while gender applies to the individual's self perception. I know that I'm probably going to step on some toes here, because I've read so many conflicting views regarding sexuality and identity. If I say something that resonates positively with one person, I will have also said something that rubs another person the wrong way. A reader could argue the semantics of what I'm saying, or use these words as a framework to engage their own exploration of the issues involved.
Biological males in this setting could masquerade as female of they wanted to live a more adventurous life. Perhaps choosing to engage in exploration, even combat with neighbouring bandit groups or vicious creatures in the darkness. Such a story might play out as a gender-reversed "Mulan", but as soon as the male sustained any kind of injury, their masquerade would be exposed within hours (at most). There might be cunning leaders of communities who are males disguised as females, but what does it mean to be a strong dominant figure in a matriarchy when you are not female? That is a more interesting question to me, the simple reversal of gender doesn't quite feel right and that's where I'd probably be interested in getting someone more acquainted with such issues to give me their input into the situation, and their interpretation of how this might play out in the various cultures of the setting.
Biological females could similarly masquerade as males. Perhaps they prefer to exist below the radar, among the lower classed males who are generally ignored by those who wield power. I'm seeing female assassins hiding among the males who trade spices and cloth in local markets. Females who dress as entertainers (akin to drag queens in our world, except that they would be "drag kings" eternally with flawless skin due to their regenerative capabilities). Some women in the setting might do this because they don't feel aggressive or assertive enough to take on the female roles of power within society, some might just have a natural feel for these gender roles. Again, there are no simple blanket answers to why a woman might masquerade as a male in this setting, that's a question that needs to be answered by the individual.
Taking some cues from anime, there are many stories of girls dressed as boys and boys dressed as girls and many of these could be used as inspiration fodder in the Darkhive. Men doing women's roles, women doing men's roles... it's all just a case of people doing whatever is necessary for their ongoing survival. The only difference here is that it's more than simple social acclimatization, the fungal effects on mammalian biology literally do make females more suited to physical activity than males.