FWIW, I have been using skins for my Apple laptops from Gelaskins. What I like about them are three things:
- They are easy to apply and re-apply.
- They are custom fit to a variety of Apple models.
- They not only have hundreds of designs to choose from, but you can also provide them with a copy of a design that you prefer.
The only note of caution is for Apple laptops that do not have built-in fans, and rely on passive thermal cooling. Adding these to both the top and bottom of your laptop may affect how well your laptop can stay cool. The MacBook Air M4's are known to run a bit hot.
One option to resolve this, would be to use a laptop cooler. These are typically aluminum "trays" that sit under the laptop that have built-in fans.