verbally told me to only declare anything over $10K.

Sounds like a trap to me.

By “declaring” I’m not necessarily saying an itemized list of every tiny item you bought, especially if you’re under any limits. But I would be prepared to show all of it if asked. All it takes is one border guard having a bad day to make a difference.

And expressly going to another country to buy a product outside the limits and then sneak it back in to avoid duties is entirely different than some souvenir trinkets and candy.

If you declare the laptop, the border guard might just wave you through without making you pay the duty. If you don’t, and they catch you in a lie, good luck.