Cannot emphasize this enough. Treat that top like it's a newborn baby or maybe a mirror for the JWST. Keep dust off it and be VERY careful what you sit it on while working on the back side.
I use "router mats" (and make sure they're totally clean!) underneath it, even when setting it on the hollow form. Never had an issue with dents.
https://www.rockler.com/non-slip-router-mat