The thing that having an overall architecture buys you is conceptual clarity. That lets someone much more easily understand what is going on. You need to have a

The thing that having an overall architecture buys you is conceptual clarity. That lets someone much more easily understand what is going on. You need to have a minimal set of ideas that are well thought out and explained. Just saying "YAGNI" and "KISS" doesn't actually make the resulting code simpler. Why? You do have some things to build and refusing to lay out a plan for what that is going to be doesn't stop that. It just means that the complexity doesn't have a clear narrative