I am using elevation API to get particular heights at some locations

https://maps.googleapis.com/maps/api/elevation/json?locations=39.7391536%2C-104.9847034&key=myApiKey

{
   "results" : 
   [
      {
         "elevation" : 1608.637939453125,
         "location" : 
         {
            "lat" : 39.7391536,
            "lng" : -104.9847034
         },
         "resolution" : 4.771975994110107
      }
   ],
   "status" : "OK"
}

But getting the elevation at some point is not quite that I need.
What I need is the heights across the whole map, with some provided resolution, so I could draw 3D terrain in WebGL2 or WebGPU like is done here. Google provides the possibility to provide a path, but it is along a line.