I don't get. You can successfully deliver products on time for clients whilst freelancing, but when it comes to your own product you jump around not able to get a single thing done? Since you freelance, I'm assuming you're already familiar with prototyping/moving quickly - so what's the problem here?

Build your MVP quickly. It doesn't have to be perfectly coded with the utmost best practices or with the most efficient algorithms. You will be reiterating and rebuilding it anyways as your idea evolves. Ship as quickly as possible. If the idea completely flops, it'll be because there was simply no market for it, not because of how quickly it was pushed out.

Cut out all the excess that's completely worthless for shipping quickly. Stop buying random books unless you absolutely believe you're completely ignorant in that area, and that your product cannot succeed without it. Don't buy new domain names and new servers - just use one that you already have to get the app up and online ASAP. Don't build your own tools if there are free 3rd party resources already available.