On iPhone X, iOS 14.3 the fix was to turn off motion & fitness tracking for Health. Health then showed the exact number of steps from Garmin Connect app on every sync. Settings>Privacy>Motion & Fitness…
I was able to fix this by going into Apple Health, Steps, Data Sources and then Edit and dragged Connect to the top right under Apple Health.
I still have the same issue, what is a workaround for this?