Boolean

The #[Boolean] property type will render a lightswitch input in the field properties panel.

use Solspace\Freeform\Attributes\Property\Input\Boolean;
// ...

#[Boolean(
    label: 'Is Required',
    instructions: 'Enable this to make the field required.',
)]
protected bool $isRequired = false;

Result

The default value will be inferred from the PHP's property value, in this case false.