I like to use millimeter paper as my notepad under keyboard. This way a have place to take notes or draw something always in place. But there was a problem with curling corners, so i used folded paper corners. But now i made those plastic "corner shields". Now my table looks clean and nice. So I recommend millimeter paper for you also. Try it.

Those corners are only 3.5mm thick. After printing you can click parts together, but it's better to use superglue also. This is nice quality millimeter paper: https://www.amazon.de/-/en/gp/product/B0BSTYQ3V3