Hey chaz mee — thanks for your thoughts.
Even during early design phases, there are absolutely huge benefits to jumping into code. IA should be a high priority early on and building a basic template with code allows you to define hierarchy and navigation with genuine user input.
I really recommend building a basic web app, embedding Hotjar and gathering some genuine user feedback. Your users should be involved at every stage, not just once product owners have approved of something.
I am definitely not discouraging ideating in Sketch. Instead, I am keen to place more emphasis on the absolute benefits of a designer diving into code.