This being said, I've been self employed for several years, so this may have changed since ~ 2021, but I don't think it's likely.
Also, the landscape has changed, and some job posting may have been made during more optimistic moments, and they may just be stale, rather than fake.
I have referred many people to "WorkAtAStartup" in recent years who have had quite a bit of success. While it's unfortunate that you are not having the best of luck, definitely be optimistic and continue to try! There are many great companies that recruit through the YC boards, and I recommend using WorkAtAStartup to have the best chances of response, even more so than their direct job listings.