I am using MarkerClusterer. When I have two or more markers on the exact same spot, The API only displays 1 marker - the top one. But somehow I want to show all the markers
MarkerClusterer has option to define maxZoom upto which cluster should be visible in map. You can set its value to 18, so it wont show cluster when user zoomed in to its maximum:
const markerCluster = new MarkerClusterer(map, markers,{maxZoom: 18});