Karabiner-Elements: map emoji key to right option, complex modifications

Question

I am using Microsoft keyboard on a macOS and I would like to map the Emoji key to Right Option. I would like to do it because it would like to use Right Option as a modifier for typing Polish diacritic characters. This is how I type them on a regular Mac keyboard.

With Karabiner-Elements Event Viewer, I checked that the Emoji key, when pressed on my keyboard, is actually a combination of keys: Space + Left Option + Left Command + Left Shift + Left Control.

Therefore, I tried to write a complex rule to map this combination into Right Option. But it does not work as expected.

{
  "title": "emoji to right option",
  "rules": [
    {
      "description": "emoji to right option",
      "manipulators": [
        {
          "type": "basic",
          "from": {
            "modifiers": {
              "mandatory": [
                "left_alt",
                "left_gui",
                "left_shift",
                "left_control"
              ]
            },
            "key_code": "spacebar"
          },
          "to": [
            {
              "repeat": true,
              "key_code": "right_alt"
            }
          ]
        }
      ]
    }
  ]
}

Thank you in advance if you could suggest a solution.

Best wishes, Mariusz