me_irl

... probably not, no.

Ous/Osu is ... generally seen as a kind of brutish/meathead/dudebro/gymrat kind of word, by many Japanese who are not martial artists.

Its... not like everyone in Japan is a martial artist.

Ous/Osu is a word that, to myknowledge, is only really used seriously by martial artists, most others would only use it ironically, to pantomime being a big strong fighter person.

If you were just in an orgy in Japan, using ous or osu would be something like you performatively acting like a chud, something like that, kind of.

That's my personal take on it, anyway, here is another:

https://www.adamcarter.us/respecting-cultural-context-osu-it-isnt-always-appropriate/

The increasing use of the word ‘Osu’ (or ‘Oss’, or a million other incarnations) has become strangely common. It’s often used as a catch-all greeting or acknowledgment. However, this broad usage overlooks important cultural and historical nuances.

Many people misunderstand it and use it as a universal Japanese greeting, but its origins tell a more specific story. The term is not rooted in Okinawan culture – the birthplace of many traditional karate systems – but rather in mainland Japan. It originated in military and sports contexts.

In Okinawa, however, the term is often considered militaristic, reflecting the influence of Japan’s early 20th-century militarization.

To many Okinawans, the term can carry connotations of dominance and rigid hierarchy that feel out of step with their values and traditions. While they may not openly express discomfort (out of politeness), using the term in an Okinawan dojo or when addressing an Okinawan instructor can be seen as disrespectful.

...

Outside of your dojo, its use can sound casual and with a very masculine tone, which may not be respectful in certain situations. Its history with militaristic contexts can sometimes make it feel out of place or unintentionally exclusive.

I write on mobile, its formatted fine for mobile.

I (and my fellows) were taught to start with just either 'osu' or literally verbalizing the kiai as 'ki-ai', but were also told that many different sounds can work, do what works for you after you get the basic concept down.

Some stuck with osu/ous or kiai, others ended up with something like hai or sai or ee-sah or 'tsah or 'tsuh or 'tsuu...

Many possible variants... i remeber hearing 'go with your gut', entirely unironically.

EDIT: Now that I think about it more, if you kept track of who was making what kind of kiai sound at a tournament, you could probably be reasonably confident as to which dojo they were from, at least at beginner to intermediate levels, hah!