Dmax Armor Glass
Dmax makes a pretty great screen protector for the Moto X4, and you'll get two for the price of one. Their glass promises 99.9% clarity, it scores a 9H on the hardness scale (same as all the high-end brands) and it's very easy to install.
They add extra coatings on top of the tempered and strengthened glass to prevent fingerprints, and cut down on those small micro-scratches you always see on screen protectors. Then, there's a limited lifetime warranty. That said, you get two, so you won't even need the warranty. If one breaks or you mess up the installation, try the second one.