Puzzle Frame (Fully customizable, Fusion 360 file included)

I'm so excited to share this idea! We like to do puzzles, and we like to have them dry mounted to put on the wall. Ideally we'd frame them, but framing is so expensive it's just crazy. So when my girlfriend asked if I could just 3D print a frame I was like "well... I mean... yeah..." Of course, the puzzle was a panoramic puzzle more than three feet wide. Sure wasn't going to be printing that on my MK2 MMU. It was obviously necessary to split the frame into multiple pieces, but how many, and how