>> I felt like by forty I needed to move on from engineering [or] be like older workers [who] moved too slow, stuck in their ways, unable to change

This is a terrible idea. It's not age, it's attitude and approach.

I replied to OP on this here: https://news.ycombinator.com/item?id=41405231

Not mentioned in that, adding here: You can't invent viable things unless you know the stuff of which they are made. Bigger/harder/newer things are built on more/harder/newer stuff.

Deep learning is largely incompressible. Practical (applied) mastery takes 10,000 hours times the things you need to know.

Ergo, always keep learning, use "more years" to outcompete by sheer accumulation of understanding what new things are made of and how they work together.

Become that staff eng, principal eng, or engineering fellow who can, and does, do more impactful things.

But only if it's a fit: https://growthco-op.com/wp-content/uploads/ikigai-1-1024x968...