Finding things in Finder · Reveal in Finder across the app
How do I find the files I've actually been working on, and open their folders in Finder?
Short answer: Open Storage Profile and check What you actually work on: it lists files you've opened recently, grouped by type, each with its location and a reveal-in-Finder button. It's all measured on your Mac.
Open Storage Profile (from the More menu or its card on the Home screen) and look at What you actually work on. It shows the small set of files you've opened recently, broken down by type and by the folders you work in most.
Expand the list of files to see each one's name, location and when it was last opened, with a reveal-in-Finder button to jump straight to it.
Everything on this screen is measured on your Mac; nothing personal leaves it. It's also a handy way to see what you'd want to keep on your built-in drive before moving older things to the external one.