Komorebi

you should be fine in any hostel that's not rated horribly on hostelworld.com and you can generally choose a female only dorm. i've enjoyed sakura hostel and quite a few from the khaosan hostel chain. keep your valuables locked up in the hostel and keep to streets where there's people late at night and safety shouldn't be an issue... as a tourist you'll probably be in more crowded places overall. i did airbnb once for okinawa but it can be less set-it-and-forget-it than hostels as you generally have to pick up keys and depending on the accommodation the owner may be there with you and thus you might feel obligated to make small talk... you have to rely even more on reviews when choosing airbnb imo.

if hostels are not private enough for you the toyoko inn is a decent business hotel with a lot of locations as well.

yes, i recommend hostels if you want something cheap. the one i went to (i don't remember which one right now) didn't have towels for showering tho (i used one of my shirts instead lol), plus the bath/shower was kinda narrow so just be mindful of things like that. having little privacy sucks, but it shouldn't be a big problem if you're mostly out and about exploring anyway. you can also try capsule hotels, which are quite similar to hostels.

or if you just really need a place to stay for the night you can opt for manga cafes. you won't have a real bed to sleep on, but they're soooooo cheap for one night. plus, the showers are always good and clean (the ones i've been to anyway). i don't recommend it if you have a lot of baggage on you though since the tiny cubicle is all the space you'll have.

totally forgot that you need to make a membership card when using manga cafes. so if you want to avoid all that process then nvm.....