Thanks you were missing an array of arrays
$repeater = 'field_62e5ba2733cea'; // field key of repeater
$value_john = array(
// nested array for every row of repeater
array(
// field key => value pairs for each sub field
'field_62e5ba3233ceb' => 'block title', // title field
'field_62e6bd4119dc1' => array(
// nested repeater
// field key => value pairs for each sub field
array(
'field_62e6bd5e19dc3' => 'link title',
'field_62e6bd6419dc4' => 'link url',
'field_62e6bd6a19dc5' => 'link fa icon',
),
array(
'field_62e6bd5e19dc3' => 'link title',
'field_62e6bd6419dc4' => 'link url',
'field_62e6bd6a19dc5' => 'link fa icon',
),
),
// next row in nested repeater
),
// next row in repeater
);