Accessing livewire select data

I need to access select data for my function. But it says that $date is an undefined variable. What exactly I'm doing wrong when I'm trying to access it? My blade:

                    <select class="custom-select-box" name="date" id="date" wire:model="date">
                        @foreach ($available_dates as $available_date)
                            <option value="{{ $available_date }}">{{ $available_date }}</option>
                        @endforeach
                    </select>
                    @error('date')
                        <div class="text-sm text-red-400">{{ $message }}</div>
                    @enderror
                </div>

Function:

class AppointmentsCreate extends Component
{
    public $first_name;
    public $last_name;
    public $email;
    public $phone_number;
    public $date;
    public $option;
    public $comment;
    public $time_slot_id;

    public $date_input;

    public function rules(){
        return [
            'first_name' => ['required'],
            'last_name' => ['required'],
            'email' => ['required', 'email'],
            'phone_number' => ['required', 'numeric'],
            'date' => ['required', 'date',  new DateBetween],
            'time_slot_id' => ['required'],
            'comment' => ['required'],
            'option' => ['required'],
    ];
    }

    public function render()
    {
        $times = TimeSlot::where('status', 1)->get();
        $date_today = now()->addHours(6);

        if ($date_today->isTomorrow()) {
            $date_today = now()->endOfDay();
        }

        $times_today = TimeSlot::where('status', 1)
        ->whereTime('time', '>', $date_today)
        ->get();
        $available_dates = array();
        $appointments_today = Appointment::whereDate('date', Carbon::now())->whereHas('time_slot', function ($query) use($date_today){
            $query->where('time', '>', $date_today);
       })->get();
            if (count($appointments_today) < count($times_today)){
                array_push($available_dates, Carbon::now()->format('Y-m-d'));
            }
        for ($i = 1; $i < 7; $i++) {
            $appointments = Appointment::whereDate('date', Carbon::now()->addDays($i))->get();
            if (count($appointments) < count($times)){
                array_push($available_dates, Carbon::now()->addDays($i)->format('Y-m-d'));
            }

        }

      //a piece of code where i receive an error
        $appointment_time_ids = Appointment::orderBy('date')->get()->filter(function($value) use($date){
            return $value->date->format('Y-m-d') ==  $date->format('Y-m-d');
        })->pluck('time_slot_id');

        if($this->date->format('Y-m-d') == Carbon::now()->format('Y-m-d')){
            $time_slots = TimeSlot::where('status', 1)->
            whereNotIn('id', $appointment_time_ids)->orderBy('time')
            ->where('time', '>', $date_today)->get();
        } else {
            $time_slots = TimeSlot::where('status', 1)->
            whereNotIn('id', $appointment_time_ids)->orderBy('time')->get();
        }

        return view('livewire.appointments-create', compact('available_dates', 'time_slots'));
    }


}