Hi Mr Michael J Gray,
Thanks for coming to Apple Support Communities for help with the Health App and accurate step tracking. It sounds like you are only using your iPhone X and not an Apple Watch.
Make sure your iPhone has the latest update: Update your iPhone, iPad, or iPod touch
Be sure Settings > Privacy > Motion & Fitness > Fitness Tracking and Health are both enabled. If they are, toggle these settings off and on.
Restart your iPhone: Restart your iPhone.
If we were mistaken and you are using an Apple Watch, please follow: Get the most accurate measurements using your Apple Watch.
Let us know how it goes.
Have a fantastic day!