You are starting a new development, and:
I know that feeling. On the first product I built, I missed half of the requirements. I was blocked for months until I figured them out.
So I built a framework: the technical pyramid of product development.
From infra to UI, it covers every technical aspect you have to work through as you build and ship. It also comes with a bank of questions you can use to discuss with engineering and start your investigation.
Once you use it, thinking through the technical solution becomes simple.
Let me also make it clear: you should walk through these questions before you start building. Depending on whether you are building something new from scratch or a simple or complex feature, some of these will be more important than others.
Let me be even more clear: for many questions you won't have all the answers in the beginning, and that's okay. But this pyramid will help you get the most clarity possible before you start building. As you move through the build, you will know what you still need to iron out.
And one last comment: it won't save you from all the unexpected things that usually come up during delivery, but in my experience it will get you to 80% clarity.
Go layer by layer, from infrastructure up to the UI. For each layer, research, ask engineering and, best of all, set up a workshop where you work through the questions and decisions together. The aim is to surface the big technical decisions, uncertainties and potential showstoppers.
Every layer has the same four blocks: