How to Downgrade
If you start seeing issues on the latest build, you aren't stuck. You can downgrade to another version of Android if your Nexus 5X starts to struggle.
If you get tired of dealing with bugs you can get off the latest Nexus 5X's Android 8.1 Oreo update whenever you want.
If you’re unfamiliar with how the Android downgrade process works, have a look at this guide from the folks over on the Nexus Help Forums.
This downgrade walkthrough will take you through the steps you need to take in order to move off your current version of Android.
There's no guarantee downgrading to an earlier Android 8.1 build, Android 8.0 or Android Nougat will help fix your issues, but it's worth a shot if the latest Android 8.1 update's causing major issues on your device.