What is the point of this?how can I earn money,they nerfed all the other heists

Tbh, currently the only heist that's solo friendly I'd say is the Kortz Center Heist (imo), due to the short 10 minute cooldown it has and how fast you can complete it. Other than that we do have Cayo Perico, but once you've completed that heist, you'll need to wait around 2 hours (in real time, yes) as a solo player, or 48 minutes (also real time) if you finished it with another player in the party. That said, it still pays more than the Kortz Center Heist, so I'd say while you wait for the Cayo Perico cooldown, you can run Kortz Center, and then once the cooldown is up, go for Cayo Perico and just repeat.