If you are trying to access the values, you can use the keys attribute
var myFireBaseObj = {
  "users" : 
  {
    "GSIgfyiEGtZs5reYe4SpwFJVxDC2" :
    {
      "email" : "anic@hotmail.com",
      "password" : "Dava123",
      "score" : 0,
      "username" : "Anic2",
      "zdate" : "2-3"
    },
    "OHxA5ARnbYdsy9Ga1nxDy0gZQBv1" : {
      "email" : "dava@hotmail.com",
      "password" : "Dava123",
      "score" : 3,
      "username" : "dava",
      "zdate" : "01-03-2021  11:53"
    }
  }
};
console.log( Object.keys(myFireBaseObj));
// if you want to get both values and keys / users etc seperately as objects
var keys = Object.keys(myFireBaseObj );
var values = Object.values(myFireBaseObj );
console.log(keys[0]);
// put your attribute you want here
console.log(values [0]['...']); 
Option 2: if you want an array back, use map for e.g. adapt it below
 Object.keys(myFireBaseObj).map(function(a,i){
 // whatever you want in the array you map it here
 // you have to customize the nested levels
 return
 [i,myFireBaseObj[a].blahBlah.. ,
 myFireBaseObj[a].password] 
 })
Update: Added sample to show for loop to get the key, values
for (var key of Object.keys(myFireBaseObj)) {
    // this will give you the key & values for all properties
    console.log(key + " -> " + p[key])
    // .. process the data here! 
}