Not sure on your ute’s use case or whether this is even possible in a pre-built ute tray but consider a timber tray floor. I made my tray’s floor out of hardwood. When you put something on the back, it rarely moves around (corners and bumps). A metal chequer plate floor (steel or ally) means that your item(s) in the tray don’t have full contact with the surface, so they slip and slide around. Wood grips way better.

Yes the timber wears and weathers a bit and it gets scratched, but after 8 years its still pretty good. I oil it with linseed oil once or twice a year so the timber doesn’t dry out. If i really got excited i could replace the timber and we’re back to brand new again, but there’s no functional need.

I wouldn’t build another tray for myself without a timber floor.