Attractive way to hide screw heads in 8mm oak
There are trim screws with very small heads. They come in stainless steel. The trim needs very little support so the small heads are not a structural problem.

A  woodworker's technique is to use a small sharp gouge (a curved chisel) to lift a small patch of surface from the wood, bend it back, drive a trim screw in the divot created by the gouge, and then glue back down the lifted patch.