I am about to do final assembly for my plywood organizer insert for a boardgame.

The wood is gonna stay inside the cardboard box for all its life, so humidity isn't gonna be a problem (or rather, it would destroy the cardboard components before the plywood).

It's 4mm thick plywood of the cheapest kind I could find.

I have sanded all the exposed edges with 400grit, and all the edges that I'll be gluing with 50grit.

Do I need to cover the wood with a clear layer of protective something? All resources I could find on the internet talk about waterproofing, but I don't need that…