Static Webstie - Render Dropdown Json Data

Question

For static website, where we need to show dropdowns of predefined/organized json data (>50MB). Problem is Loading all the data while launching page killing user's browser (not responding). How to handle this in an effective and cost optimized manner?

Currently Website uses plain html and js.

Model page looks like this:

Sample Json hierarchy data:

{
  "level-1": [
    {
      "level-2-1": [
        {
          "level-3-2-1-1": "value1",
          "level-3-2-1-2": "value2"
        }
      ],
      "level-2-2": [
        {
          "level-3-2-2-1": "value1",
          "level-3-2-2-2": "value2"
        }
      ]
    }
  ]
}

Thanks in Advance.