Looks like I found what could be a relatively durable finish which doesn’t scratch too easily. I’ve tried it on walnut and oak. For the walnut frame, oil-based stain was followed by three coats of Watco Danish Oil, then two coats of wipe-on poly. I waited for several days after each coat to make sure they are cured. I sanded with 600 grit wet SP the last two coats of Watco Danish Oil just after application of the oil while it’s still wet, and the last coat of the wipe-on poly.
The oak (left on the bottom photo) was dyed, then coated once with Danish Oil, then stained followed by two coats of wipe-on poly.
These finishes are hard enough, so they can’t be scratched with fingernails, which is a big improvement compared to walnut after several coats of Waterlox Original. The Waterlox finish is heat, water and water resistant but is easily scratched, including with fingernails.
-- "If you're not counting the ripples when throwing pebbles in the water, you're wasting your time."