YXXSDP Bendable Acrylic Sheet Panels, Clear Thin Plastic Sheet Flexible Board with Protective Paper, for DIY Craft Projects, Picture Frames, Outdoor (Color : 1.22x2m/4x6.6ft, Size : 1.2mm)

Not an expert. Just my thoughts I would say 1/4” plywood sandwiched on top of 1/4” acrylic sheets which can bend more easily than plywood. The acrylic will resist snapping the way plywood may and it won’t be as compromised by drilling through it. The screws connecting them will keep the plywood in place. Finally, when you start to bend it by pulling it together, wet the plywood and it will flex easier.