He didn't address it because it is a stupid notion.

If Russia breaks ceasefire you can go back to your plan of slugging it out, it makes no difference to your situation to at least try, but there's also the possibility that Russia honors it which would be favorable. Zelensky though is delusional, he wants a full sweep, anyone in his position would but it's not realistic. Like Trump told him, he has no cards to win. The most he can hope for is to walk away from the table alive and he only has that option because of outsiders. Ukraine must compromise to survive, sometimes the lizard that sheds its tail gets away and lives out the rest of its life. Now's that moment.