How do you guys find someone on reddit or some other online platforms?

I have seen a couple of posts on reddit and on insta too claiming that they met on reddit or maybe on insta or other platforms. Like tinder, bumble, honge etc make sense that they're made for this so very obvious but how do they discover people on say reddit and insta? Is it like they slide into dms say hi or whatever and just keep going or something like that? I have heard of gc in insta but still there were a lot of things going on and they started to chat randomly with each other.

Many of them say that they've found their life partner there. Huhh? I just can't digest it by myself. I have texted a few people who posted saying "anyone up for a chat?" and got ignored by them 😭. Is there something wrong with me, like am I the exceptional case or is it always like this with others too?

If someone isn't getting any reply, how will they find someone? Does that mean one should dm many people in order to get replies from few?