video about it: https://youtu.be/IDdDcCu4VJk

I only have a few printing guidelines. Firstly, make sure your adhesion is on point, as it's a long print and can warp. I'd probably recommend PETG but I'm sure PLA could be suitable if you're not leaving it in super hot environments. I've printed a few in PLA without any issues so far but obviously you're putting your cards in it so I'd err on the side of caution, thus PETG.

Here are the magnets in the video. I've used the 8x3x1 set for the design, but one time I ordered them the sizing was off and they've been in and out of stock. I've included the STP and F3D files so you can change dimensions as needed for magnets or storage capacity.

8x3x1 Magnets
https://www.amazon.com/gp/product/B07QFHGZZF

5x2 Circle Magnets
https://www.amazon.com/gp/product/B08CN7J2S3