You already know the answer to this Herin. App Inventor apps do NOT work in the background.
Running in the background was discussed with you Broadcast hub (solved) - #34 by Herin_Love
specifically to use a work around to prevent the Screen from falling asleep (dormant) while collecting location geocoordinates.
Either use a Stay Awake block routine using a Notifier
or you use Taifun’s Tools Extension: https://puravidaapps.com/tools.php
Using either an extension or a block routine drains your device battery rapidly . These work around methods are not running the app in the Background, they force the app
screen to stay open .
So STAYAWAKE to keep the Screen on.
Regards,
Steve