The ELEMNT app will push its data across to Apple health and regular intervals throughout the day to update it. If you want your step metrics (for example) within Apple Health to be only from ELEMNT RIVAL then you will need to set this up within Apple Health.
Within the Apple Health Summary select Steps then scroll down to the bottom of the page and select Data Sources and Access. Under Data sources move ELEMNT to the top. If more than one source of steps is available then ELEMNT RIVAL will take priority.