How to make CodeIgniter 4 date validation to enable users to submit only future dates?

I'm struggling with my date form. This is my View:

<div class="form-group">
       <label for="date">Date</label>
       <input type="date" name="date">
       <span class="text-danger"><?= isset($validation) ? display_error($validation, 'date') : '' ?></span>
</div>

I'm sending date to my controller and I wanted to display an error if the input date is current or before the current date. Here is my controller:

$sysDate = date("Y/m/d");

$validation = $this->validate([
    'date' => [
         'rules' => 'required|greater_than[' . $sysDate . ']',
         'errors' => [
               'required' => 'Appointment Date is required',
               'greater_than' => 'Date should be in the future'
          ]
     ]
]);

        
if(!$validation){
    return view('dashboard/index', ['validation' => $this->validator]);
}
else{
    echo 'Valid';
}

After doing this, I'm getting an error even if I sent a date in the next days. Is there any solution for this or should I make a custom validation rule?

So last night, I dug up a lot and have found answers for my own questions. If you viewer are having the same problem as I then I guess my own answer here will help.

First I look out for CodeIgniter\Validation\FormatRules to look for the compiled validation rules. Then looking at the given rules, I understood that I wanted to make. Here I made a function inside the FormatRules.php instead of making other custom validation rules file and coded my own rule:

public function future_date(string $str = null): bool
{

    $curdate = date("Y/m/d");

    $date1 = date_create($curdate);
    $date2 = date_create($str);

    if($date1 < $date2)
    {
        return true;
    }
    else{
        return false;
    }
}

`

Then in my controller, I made this validation line: 'rules' => 'required|future_date'