Galaxy S9 / S10

Start Device care from phone settings. > Tap Battery. > Tap the 3-dot menu > Settings > Disable all toggles (except Notifications). > Tap Sleeping apps. > Exclude Pedometer using the trashcan icon.

Galaxy S8

Open Settings > Device maintenance > Battery >Unmonitored apps. When inside the unmonitored apps menu, tap the 3-dot menu. Now you can exclude Pedometer from the App power monitor.

On other Samsung phones, the path may look like this:

Phone settings > Applications > select three dot menu (top right corner) > Special Access > Optimize Battery usage > Find Pedometer app on the list and make sure that it is not selected.