eCharts tooltip with pointer

i need to get the eCharts tooltip on the line with the pointer like this:
pic1

but so far my tooltip is “floating” in the chart with no pointer:
pic2

my config in a PHP page:

'tooltip' => [
    'trigger' => 'axis',
    'axisPointer' => [ 'type' => 'cross' ],
    'axis' => 'x',
    'backgroundColor' => 'rgba(250,250,250,1)',
    'borderColor' => '#5d00f3',
    'confine' => TRUE,
     
    'textStyle' => [
        'fontWeight' => 'bold',
        'fontSize'=> '17',
        'color' => '#000', 
    ],
],

how can i create a pointer to follow the line, the doc is not very clear to me:
https://echarts.apache.org/en/option.html#grid.tooltip.position