Before you go about how "stack isn't important, skill is", the purpose of this post to understand what the current market trend is for backend.
A bit about me, I'm a backend dev with experience in Node.js, MySQL and MongoDB. Around 4 YoE.
My goal is to work in a company that serves customers at scale, and to learn how to engineer at scale. If you work in such a company / know someone who does, what stacks are you/they using and how are they using it? I'm seeking answers in terms of language, DB, cloud providers, etc.