Enter date from string to mysql database in laravel

I'm trying to load an excel file which contains dates as strings formatted as dd.mm.YYYY. I want to parse the excel file and save the values into the mysql database. I'm able to do this without an issue while creating a new entry into the database with a create form that has a selectable html date input in the form of:

<input type="date" id="expiry_date" class="form-control @error('expiry_date') is-invalid @enderror" name="expiry_date" value="" required autocomplete="expiry_date">

Below is the import function inside the controller that uses Maatwebsite's excel class.

 public function import()
{
    Excel::import(new excel_import(), storage_path('excel_file.xlsx'));
    return redirect()->route('index');
}

This calls the excel_import class which is shown below:

public function model(array $row)
{
    try
    {
        $date = Carbon::createFromFormat("d.m.Y", $row[5])->format('Y-m-d');
        //$timestamp = strtotime($row[5]);
        //$date = date("Y-m-d", $timestamp);
        return new Item([
            'user'       => $row[0],
            'name'       => $row[1],
            'expiry_date'        => $date,

        ]);
    }
    catch(Throwable $t){
        return null;
    }
}

Note that the date variable I'm trying to enter is named expiry_date. I've tried getting the date format from Carbon and from the timestamp(as in the comments) but to no avail. In the model I've tried setting it as:

 public $casts = ['expiry_date' => 'date:Y-m-d',];
 public $dates = ['expiry_date',];

Also note I've set up the expiry_date variable as follows in the migration:

$table->date('expiry_date')->nullable();

I also used dd in the create form and in the excel_import class which showed but variables were Carbon datetime instances. The result is a null field for the expiry_date variable. If I don't set expiry_date as nullable it returns an error SQLSTATE[HY000]: General error: 1364 Field 'expiry_date' doesn't have a default value. I'm truly stumped, any help would be appreciated.

via Chebli Mohamed