how to use associateArray as a key in other associativeArray in PHP (just like using HashMap as key in another HashMap in JAVA)

In Java, we can use HashMap as a key in other HashMap. I’m using an associative array as a map in PHP. Now there is a need to store an associative array as a key in another associative array.
I asked ChatGPT and it presented a lengthy solution:
Suppose $map is an array that I want to use as a key:

    ksort($map);
    $key = serialize($map);

    if(!isset($main[$key])){
        $main[$key] = 0;
    }
    $main[$key]++

Yes, I need to use ksort because the next $map could contain the same array but keys could be in a different order.

I also used spl_object_hash instead of serialize but it didn’t work. please suggest an optimal approach just like hashmap in java.
Also, I used splObjectStorage class by type-casting the array into an object but it gives incorrect results.