how to get value from inside a variable

In my code, the result of total_tax_1 is 0 even tho there are any value stored in tax1_amount.

public function store(Request $request)
{
    $sum_sub_total          = (@count($request->warehouse_details)>0 ? array_sum(array_column($request->warehouse_details,'dpp_subtotal')) : 0);
    $total_taxes            = 0;
    $totalTax1              = array_sum(array_column($request->warehouse_details,'tax1_amount'));
    $totalTax2              = 0;
    //...

    if($request->is_use_tax == 1){
        $tax = Tax::find($request->id_tax);
        $totalTax2 = ($sum_sub_total * $tax->percentage);
    }
    $total_taxes = $totalTax1 + $totalTax2;

    $data_wh = [
        //...
        'total_tax'                 => $total_taxes,
        'total_amount'              => $sub_total_after_disc + $total_taxes,
        //...
        'total_tax_2'               => $totalTax2,
        'total_tax_1'               => $totalTax1,
    ];

    $warehouse_details = [];

    //create list Wh Detail
    $i = 0;
    foreach($request->warehouse_details as $wh_detail){
        //...
        $tax_per_row = 0;
        if($sub_total_after_disc != 0){
            $tax_per_row = (($wh_detail['subtotal'] - $disc_item) / $sub_total_after_disc) * $total_taxes;
        }

        $pph22Amount = 0;
        $pph22Rate = 0;
        //..
        $pph22Amount = MyHelper::processTax($amount, $wh_detail['id_pph22'], TransType::$TO_PURCHASE_INVOICE);
        //...
        $data['sub_total_tax']              = $tax_per_row;
        //...
        $data['tax1_amount']                = $tax1_amount;
        array_push($warehouse, $data);
    }

    //create Wh
    $warehouse = Warehouse::create($data_wh);
    if(!$warehouse){
        DB::rollBack();
        return response()->json(false);
    }
    //create Wh Detail
    $create_wh_detail = $warehouse->warehouse_details()->createMany($warehouse_details);
    if(!$warehouse_details_check){
        DB::rollBack();
        return response()->json(false);
    }
    
    //...
}

I want to get the value from tax1_amount and save it into the variable $totalTax1 so I can use it when creating warehouses and warehouse_details. Is there any solution other than moving the create flow? Because I have my own reasons for creating warehouses first