Given the size of your product (50cm), I understand lightweighting is a core aspect.
But we need more details as to load cases and contextual aspects, and your manufacturing plans.
In most cases a simple solution is best and costs aren’t very prohibitive at large numbers, as long as you minimize components and processes.
What pops into mind is a conductive ABS custom extrusion rail mounted with nylon screws and spacers on a honeycomb aluminum sandwich panel. You can also consider magnetic connections or electromagnets (some toaster trays work like that)