[Discussion] Are design patterns still relevant in this web dominant field? How often is it necessary to consider a good design before starting development?

I am thinking of creating some cross-platform application that uses OpenCV, OpenGL, WASM, and NDK. Any idea on how to get started with good development methodology?

I can hack it out real quick but I am having a hard time figuring out some good methodology and design ideas to work on. I used to work on python and most of the things were pretty easy in python because of duck typing and availability of the huge amount of frameworks. I recently refreshed my C++ knowledge and want to know the situation of modern C++ development. I want to be able to use vision algorithms and render them in real-time. Any tips to get started on it?

I have experience in computer vision and python. Some web development and deployment skills too. However, I tend to create small applications and want to try some well found robust ideas.