We also launched a similar service in the past like 3-4 years back and trust me it doesn't work as you think. The problem is with the product-market fit. It is very hard to find the right people for your service and the fierce competition from all the major players makes it even harder.
If you are truly involved in the service then don't wait for the people to find and reach out to you, instead try to find the right audience and reach out to them. I know it is tougher than saying. We've tried it but unfortunately, it didn't work as we planned and that's why we shut it down after just 6 months.
Nevertheless, at least try it first. All the best.
Themes For App : https://themesfor.app
It is a site where you can download free bootstrap templates for your side-projects.
I've been running it for over 5 years now and earned zero out of it. First thing that I want to mention is that in the first place, it was not my primary intension to earn from it but from the start of this year I have started looking forward to monetizing it.
At the moment it costs me $0 to run except the standard domain cost. But in starting it costs me $500+ for the ESP.