There is a brand that makes screen (or body) protectors for phones, tablets and laptops. I have used their phone protectors and have always been happy. I don't agree with the downsides listed for this approach, they offer matte finish, I have never had an issue with the protectors yellowing, and I can source (buy) them right now. https://www.bestskinsever.com/laptop-skin
If it was just used for the top case, I think it should be fine. Mine has yellowed, but was autographed by my favourite author. :)