want to lasercut a new panel for undernieth the build palte, suggestions?

hi Everyone, I don't think I've introduced myself anywhere on here so Hello I'm Jelly. Anyway I recently picked up a Flash forge creator 2 which so far i'm really happy with, except that the build plate is not level. I know its because the wood panel that holds up the build plate has warped dramatically. I'd like to replace that panel with something made out of a different material. I originally thought I should laser out an acrylic panel but it looks like that warps too. Do you guys have any suggestions for a good material to laser cut a new panel for under my build plate?