Shelf tier riser ideas to expand storage

Apologizes if this has been covered in other posts. I searched but could not find anything. I'm looking for ideas to double my shelf space and create risers so back cases can be sceen behind the front cases. My hope is that new good movies will still be available in future years and streaming services will release more physical media. I have 1300+ DVDs, blu rays, and 4Ks in my collection. Currently they are on track shelves 8 rows 9' long. I'm getting close to capacity without removing knick-knacks. I also have the issue of being 5' and aging; climbing the ladder to reach the top shelves are getting harder. I am hoping to re-do my office/entertainment storage next year, including upgrading my shelves. I don't want to do bookcases. My idea is to get deeper shelves with a better, nicer anchor option. I'd like to be able to have two layers per shelf with a riser about half the height of DVD cases for the back movies to show. This would allow me to expand my collection and bring my top shelves lower to the ground. I'm looking for ideas on the riser section. It would need to be lightweight. I use acrylic risers for my toy display, but that can be expensive. Not sure if plywood is too heavy. Though about custom cardboard boxes but the humidity if FL can suck.