Re: military:
I found a lot of masculine-only societies... actually aren't so masculine-only, once you learn to blend in.
Act as one of the guys. Accept their style of reasoning & their directives. Learn from them as teachers, not as a competition.
Follow the style of talk & non-verbal language & sense of humor & body postures, even with details conveying submission... in details, not invitations and not sexualized.
Fill in the gaps, consideration of possibilities; come to be appreciated as a thinker & fast doer & a person that isn't in the way, instead cooperates in the style they're familiar with & understand.
Hang around if you need time to observe. Figure the subtleties. Figure points of access & informational needs they may not be covering.
Messengering & being a reliable courier & observer may be a good start. People need extra eyes almost everywhere, regardless of who they are and who they're working for. Don't judge, don't gossip, don't pry, learn to figure hierarchies, abide by them until you can find a comfortable spot that would work for -you- too.
Be courteous. Courtesy & honesty are hard to turn down flat out. Not figuring who might be an asset may be a fault of THEIR reasoning, and missing out a chance that's easier to grab, at the first start.
Most societies that are very segregated by gender /can/ be joined, if one's insistent enough but not a pain in the ass about it, and respecting of structures that've been in place for ages... while using them to own advantage, but not at the expense of others, as it's going to be well being of a pack preceeding that of the individual, unless that individual is a key-log and irreplacable in those people's eyes. Aka: Use the system, don't use the people.
All I'm saying, don't be turned down by official and claimed rules. If you've got the smarts & the skills & willingness to learn and improve and overcome deficits? You can be darned valuable, and not recognizing valuable is a loss.
Another thing: I'd look for less 'established' units associated with those well established. Transfers happen fairly often, it's a chance to get the hell away if the starting point is less than favorable after you've gotten through the basic boot camp and got something to start with and build on, and closer to having official references, or at least friends in the right spaces in case you need that sort of protection.
There's plenty of places world wide that welcome support forces who can or will be active combatants, if that's your call, as a gradual progress and / or by necessity.
Which is another entrance point.
Re: 'gypsy communities' - ignoring the G slur - you'd have to act by their standards, and not fetishize the communities. Some *are* accepting, unless you count those descendants of clan royalties families, where acknowledging them as royals within traditions is owed and not indulging on their lives and businesses is a thing of honor one cannot cross, only bow to. (Internationally.)
Family code of honor is a must. So are several languages; most Romani people, even where 'illiterate', are fluent in several languages & cultures, trans-national, often traveling for business and by being forced to, and not taking well to being fetishized by outsiders. There *are* things as honorable adoption within the cultures, for some of Romani ethnicities. But they take time, to actually live with the cultures, by their laws.
Also, which Arabic are you learning, out of curiosity? ;) Standard + Egyptian + Lybian works pretty well as far as communication is concerned, for acceptabiltiy across the world, and having solid formal even where colloquial up. They're a good match to have, regional & formal, and regional & informal but with enough formalities mingled in one gets by through administrative. Eg Arabic is particularly useful for reading the news, Lybian is useful for medical needs quite a lot, same with getting accross paperwork, standard demonstrating you're one of the people / sympathetic to cultures / seeing things from their viewpoint / working on it, and again, respectful person.