Front end development on tech startups

I am planning on writing (or recording videos) on the principles of Front End Development from my experience working on tech startups for the last 10 year.

I want to talk about:

• Scaling Web Applications
• Performance
• Testing
• Design Systems
• Version Control and Packaging
• Infrastructure
• Working with Product
• Working with Design
• Working with the Backend

What topic am I missing? What topic would you like more details?