I have no interests at all and I try to pass every day as fast as possible by playing video games which don't even interest me. How do people even find any interests at all? The moment I try anything I think, wow what a waste of time this is just in general, and then I just go back to laying around trying to pass the time as fast as possible.
I've felt this way many years now (currently 29). So, you're problem or cognitive state is not unusual, I think--I really have no interest in using the internet that much, except for music and following news, etc... As for hobbies, I feel a lack of interest and focus in most things, even those I occasionally enjoy, such as reading. Exercise helps, as does music, which I've started listening to again after years. Music is a good place to start, it doesn't require much effort and, well, there's a lot of it. It's a "safe space" for the soul, in the best sense of the term.
Before COVID, I was working (bored out of my mind), but also going to Meetups. After more than a year I can say that these regular social events definitely helped me in some crucial ways, I felt like I had something to look forward to at the end of each week, and that feeling is worth a lot more than a paycheck.
I've also considered hiking/walking long-distance as a "hobby", although now unfortunately isn't the time to start trying.