We used, as I said above, a PU (PVC? I don’t know, I’m not a polymer expert) sheet the same size as the table to protect the glass under it. 1.5mm is all you need, it rolls up nicely to set aside, and you can put maps and stuff under it to keep it visible but protected.

And the metal dice won’t shatter your tabletop like one evil d10 did mine. 😬