Dachshund puzzle toys/games recommendations

My four year old dachshund loves puzzle toys, especially in the winter when it’s cold outside. The problem is, he’s really good at them, and bores easily. The only puzzles that reliably interest him are treats hidden in cardboard boxes that he gets to destroy or (less fun) treats in a rolled up in a blanket. Commercial puzzle toys are generally not hard/interesting enough.

What are some puzzle toys/brain games that you all use to entertain your dachshunds? I need more ideas.