Well since the lid has no coils running thru it, I suppose you could cut out a piece of foam board the same shape as the hole left by the tower, then cut a small square of wood (sealed), plastic or stainless and somehow glue or silcone that to the inside of the lid to give support to the hole you just filled, then lay laminate or vinyl sheeting on the top of the lid.
Or you could just put a foam piece in the hole, silcone it in, and lay vinyl planks (flooring), thin plywood, or even ceramic tile on the whole lid.
Or you could just remove the lid entirely and build one out of wood. Many people on here have done that..
Or you could just keep all the components and scrap the freezer and buy a new one. I have seen chest freezers go on sale recently for just over $100