I'm in my 20s and the way a significant portion of relationships start in this generation is via dating apps. If you aren't using dating apps, and don't have social circles, there's just no social fabric to build from. Believe me, I've tried activities, they don't really work. It's extremely difficult to build enough rapport with someone in the space of 1-2 hours that they'll care enough to ever meet up again.
From what I read in comment threads like this, dating apps don't really work for the majority of 20-something men, either. So your choice is between paying for an app that doesn't work and going out and doing IRL things that don't work. Why would you pay for the app, when you can get the same result for free?
If you're in your 20s you should change your life so that you live a lifestyle with easy social connections and ways to find partners. Being alone too much in your age will give you permanent mental damage.
So change careers, change city, change country, change whatever is needed so that you can have a decent life.
I actually go out a lot, and moved across the world to Tokyo four months ago. The problem is not meeting people. I can make surface level connections every day of the week. The problem is finding people who want to stick around.
If it's only been four months, then you don't have to worry. To make deeper than surface level connections, find a group activity and show up repeatedly (this can be work or school as well). But perhaps the Japanese aren't too interested in making friends with foreigners? The part about moving I mentioned is also about moving to a place where people are more sociable, I don't know if Tokyo is it.
Permanent mental damage is rather from years spent in loneliness, or lovelessness, or poverty, or any other kind of unsustainable personal situation.
