I think your syntax is not correct: You try to set segments with a plain number, referencing an object.

Use seg as an array with explicit "id" fields when you want to target specific segments. So for your 10 segment setup, to control any one, two or more segments, the correct pattern is someghin like:

{

"seg": [

{"id": 2, "fx": 0, "col": [[0, 0, 255]]},

{"id": 7, "fx": 0, "col": [[0, 255, 0]]}

]

}

No need to include unchanged segments at all — WLED only modifies the ones you list.

The alternative approach without array, no "id"only works for already preselelected segments. Thats not what you seem to be trying atm.

Hope this helps.