Looking for a good sealer for masonite/hardboard

Greetings all…

I just finished an out feed/assembly table… It 4 layers 1/2” OSB then 2 3/4” MDF topped with 3/16” hardboard/masonite. I wrapped it in some maple hardwood to protect the corners. I’d like to seal the top to prevent it from swelling if it gets wet. Even though the top is ‘sacrificial’ and I’ll replace as needed, I’d still like to get some protection on it. Any suggestions? I’ve tried poly, but it’s not working out too well… Very slick and scratches very easy.

Thanks!

-- I cut that thing twice and it's still too short!