How TF do you get paying SaaS customers?

I'm in pain trying to get customers through cold email, marketing posts, videos etc... I know I have a useful product - cloud coding agents at repobird.ai but I can't get paying customers. I get some user sign-ups here and there but they seem to only use up free credits and peace out. I ask for feedback through emails and other means, nobody cares enough to do it - even when offering free credits. I just want to make a valuable product for customers and iterate/improve on it with their feedback. I'm a software engineer first and foremost not a marketing agent/sales guy so I am learning on this journey and doing what I can but nothing so far is working at all.