Angular Google Maps (AGM) has an auto fit bounds feature, that adds all containing components to the bounds of the map. To enable it, set the fitBounds input of agm-map to true and add the agmFitBounds input/directive to true for all components you want to include in the bounds of the map.

<agm-map [fitBounds]="true">
  <agm-marker [agmFitBounds]="true"></agm-marker>

  <!-- not included -->
  <agm-marker [agmFitBounds]="false"></agm-marker>
</agm-map>