(I know double-posting in AskSeddit and Seddit is bad practice but my original post barely got any attention and the issue hasn't left me alone since. Or maybe everyone saw it and didn't deem it important to reply, in which case, just downvote this instance.)

There is a neat German word: "alternativlos". It just means "without alternative" but sounds less clunky...English needs an equivalent for that.

Anyway...I never really tried dating apps. I did use OKCupid and Zoosk very briefly but it just didn't feel...right. And on Seddit, many users seem to agree that it shouldn't be your primary source for dates, if they recommend it at all. Recently though, I've started toying with the idea of installing my previous apps again and maybe add Tinder. A friend of mine has had some success but more importantly, it more and more seems like the only viable option to me.
Yea, the gold standard here is obviously the Cold Approach or at least real life interactions but to me, those just seem to risky and difficult, if I'm honest. On Tinder, for example, you at least know a girl is interested in being talked to, maybe not by you but at least in general. You can't mess up too much by picking an inappropriate moment to chat up a girl. (I know there are, supposedly, signs that a girl is interested in you, but either I'm not good at reading that, or, admittedly more likely, I never get them.) And you know that she's (probably) single, an advantage I find even more important after accidentally almost asking out a girl who has a boyfriend a few days ago.

So, you people who somehow manage without dating apps, how do you know if a girl is interested and, more importantly, even single?