I am fairly new to ecomodding but since purchasing my semi soft tri fold tonneau cover it has already paid itself off with the fuel savings. My dilemma is winter. The kind I bought is three folding frame with a leathery type cover. It will not hold the snow. The joints are plastic

. I was thinking of this for a temp winter tonneau because: keeps bed clear, even with snow it will probably help a little on highway portions, cheap and easy.
I was thinking plywood with like coroplast stapled to it to cover the topside. I already have 1 holt drilled on each corner of top bed rail from previous owners camper shell. They sell 4x8 sheets cheap close to me. I could paint/caulk the outside edges or even try to fold over the edges to reduce plywood exposure?
probably 40$ worth of material that is available on the way home from work and I have various 2x4 I could just throw two in the center for extra support.
Am I thinking to much into this?
I can't stomach the cost of the one piece bed covers yet and the foldable one is nice for the 5th wheel.
*I am working on finding another front bumper to copy big daves air dam since my bumper is 4 bolts. So I can remove in winter and run in summer.
I can't do much else because of the trucks utility purposes with the trailer, camping, etc but the tonneau cover alone has netted me 1-1.5 consistently on road trips.