Just realized my pickup bed is why my $40 cooler broke, so I built a simple rail system in the garage
Last July we drove out to a lake near Bend for a family cookout, and I slid my cheap rotomolded cooler into the truck bed like always. Problem is, that plastic bed has ribbed ridges, so every bump on the gravel road made the cooler bounce and dig in, and by the time we parked the lid hinge had snapped clean off. My uncle took one look and said, "You don't strap a cooler to ridges, you give it a flat floor." So that weekend I cut two pressure-treated 2x4s, laid them flat across the bed ribs, and bolted down a simple plywood deck with an eye bolt at each corner. Now the cooler sits flush, gets two short ratchet straps, and hasn't moved a fraction of an inch on any trip since. Cost me about $22 in lumber and bolts at the hardware store in Salem, and it took maybe an hour with a drill. Crazy part is the deck also gives me a flat spot for groceries and my tool bag, so everything rides better. Anyone else dealt with bed ridges chewing up their gear, and did you go wood, a rubber mat, or just a bed liner?
Worth noting that the ribs under there are probably doing more than you think, since those corrugations are what give the bed its strength. Bolting a deck flat across them is fine as long as you left a little gap or drain path, because otherwise water and road grit get trapped between the plywood and the metal and you get rust or rot down the line without ever seeing it start. Sounds like you hit the right fix though, since the flat floor spreads the load instead of letting one ridge take the whole hit. Only thing I'd add is checking those bolts once a season, since wood shrinks a bit and a loose eye bolt is worse than no strap at all.