7.5 Years at Amazon, and even for my side projects, I write PRFAQs and share them with my stakeholders to gather feedback. I'm a PMT at Amazon, but in my alternative life, I code on many projects, and develop infrastructure, architecture, etc, and enjoy writing as much of it as I can.
That said, work back from your customer!
Hadn't seen it that way - PR/FAQ - Press Release / Frequently Asked Questions https://productstrategy.co/working-backwards-the-amazon-prfa...
I also added an Appendix "Technical Stack Considerations," but I like the PR and the FAQ's to focus on the customer/end-user's needs. The technical details matter, but they serve the customer outcome, not the other way around.
A recent project's tech appendix had headers like "Core Technology Philosophy", "Backend Architecture", "Frontend Architecture", "Service Architecture", "Infrastructure and Deployment", "Security Architecture", "Performance Requirements", "Configuration Management", "Backup & Disaster Recovery", "Development Workflow", "Network Architecture", "Resource Management", "Development Principles", and "Scalability Considerations".
The beauty is that by the time you get to the technical appendix, you've already validated what you're building and why it matters. The technical choices then flow naturally from the customer requirements rather than driving them.