What if i’m building something no one will pay for?

Hey , I’ve been putting in 20+ hours/week on my side project for about 3 months now. A lot of the work/code is also taken from previous side projects that never saw the light of day.

I feel like i have a thousand unfinished projects, and with all of them, at some point i give up because i let the fear that nobody will pay for this take over.

How do yall cope with that doubt?