lol, no there are not female and male facilities out in the desert for example. Very much an adult and respectful approach to using the toilet, having a wash, having a period etc.
Use of language is much less of an issue when using rank, which is what is expected. They/them is used a lot when receiving an email from ‘Capt Bloggs’ for example as the rank does not indicate gender (obviously if it’s an email from someone you don’t know). If you do know someone, you would still generally use rank as a sign of respect and out of politeness.
There aren’t gendered fitness tests in the british army, they’re job specific. You want to be a chef? Great do the chef fitness tests. You want to be a mechanic? Great, do the REME fitness test.
It’s much less of a significant issue in my lived experience than this thread reads.