Big thing: Know about the roads less travelled. If your goal is synthesis you're called upon to think about how to keep interruptions low and processes resilient. Don't just lean on the procedures laid down, dig into the literature and find ways to substitute steps and reagents.

Dumb (?) example: Reduction of imines via electricity. It will likely never come up but you need to understand that the option exists and how you'd implement it if someone throws you a curve ball.

By the same token, understand your supply chain. You're not just a chemist you're the person who needs to know what you'll do if things no longer work as predicted.

And yes. Understand the ways the reactions you do use work. That's a prerequisite for the above.

PS: Scaling. Learn how to scale reactions up and down with ease. Understand why something doesn't work past a certain threshold.

Your organization might literally go from "well positioned" to "industry Leader" because you brought the fact a reagent that is no longer available can be substituted easily to their attention.