RelationManager with relation having a morph

class RoundRelationManager extends RelationManager
{
    protected static string $relationship = 'rounds';

    public function form(Form $form): Form
    {

        return $form
            ->schema([
                Forms\Components\Section::make('earlySale')
                    ->label('Early Sale')
                    ->schema([
                        Forms\Components\DateTimePicker::make('earlySale.start_at')
                            ->label('Early sale Start')
                            ->requiredWith('start_at')
                            ->reactive()
                            //->formatStateUsing(fn($record) => $record->earlySale?->created_at?->format('Y-m-d H:i:s')),
                ,
                        Forms\Components\DateTimePicker::make('earlySale.finish_at')
                            ->label('Early sale Finish')
                            ->requiredWith('finish_at')
                            ->reactive()
                            //->formatStateUsing(fn($record) => $record->earlySale?->finish_at?->format('Y-m-d H:i:s')),
                    ])
                    ->columns(2),
            ]);

    public function earlySale()
    {
        return $this->morphOne(EarlySale::class, 'saleable');
    }