Hello Giulio

Since you're using Highcharts, the chart is not showing because you have more than 1000 entries and there is an option in Higcharts API that limits it to 1000 and that is turboThreshold.

What you can do si to add wpdatachart callback where you will increase this limit:

<script type="text/javascript">
jQuery(window).on('load', function(){
    if( typeof wpDataChartsCallbacks == 'undefined' ){ wpDataChartsCallbacks = {}; }
    wpDataChartsCallbacks[3] = function(obj){
        obj.options.plotOptions = {
    series: {
      turboThreshold: 3000
     }
  }
    }
});
</script>

You will need to insert this on the same page where is this chart and also to provide the correct chart id. In our example here, we've added wpDataChartsCallbacks[3] as an example. You will need to replace "3" with the ID of your chart.

For option turboThreshold, we set the value 3000 also as an example, but if you have more data then you will change this option as well.

There's a possibility that this will break on mobile devices, but we don't have a solution for that at the moment.

You're welcome, Giulio, glad I could help.

I believe there is a callback to reverse the order, but unfortunately, I don't have an example for it.

You would need to explore Google Charts API, Highcharts API, or Chart.js API. Also, my advice would be to browse through stackoverflow.com or jsffidle.net.

Using hooks or wpDataTable and wpDataChart callbacks requires a certain level of programming skills and included support refers only to advice, so I can't help you with this.