Best way to finish this box?

Working on a Christmas gift. I got the wood scrap, but I think it’s walnut. Eventually planning to polyurethane and fill in the engraving with black paint, but I’m stuck on how/weather to stain it.

I have a few stains from various projects, but on a sample piece they showed up really dark, and didn’t show the texture that well. It’s a little too late to do boiled linseed oil.

What would you recommend?