Writing he code should be the easy part and one of the smaller time sinks actually. The fruits of the labour is in the planning, the design, the architecture and the requirements that you want to achieve now and potentially in the future.. these all require a serious amount of effort and foresight to plan out.

When you're ready, maybe you've done some POC in areas you were unsure, maybe some good skeletons work to see a happy path draw a shadow of s solution, iterate over your plans and then put some real "code"/foundation in place.

It's a beautiful process. Starting out I used to just jump into s project deep with the code first and hit that workaround button one too many times and it's far more expensive, we all know that.