After the PivotExtract process you could use the Map process to remove the "{{all}}" row or column like this:

->(new PivotExtract(...))
->(new \koolreport\processes\Map([
    "{value}" => function($row) {
        unset($row["{{all}}"]; // remove {{all}} column
        if ($row["customerName"] === "{{all}}") return null; // remove {{all}} row, remember to change "customerName" to your label column name
        else return $row;
    }
]))

You can also use the RemoveColumn process:

https://www.koolreport.com/docs/processes/removecolumn/