ReCaptcha not selectable in Submit Button Settings ➝ Spam Protection

Hi Balbooa-Team,
I've followed the instructions from this tutorial regarding reCaptcha: https://www.balbooa.com/help/tutorials/forms/privacy-and-security/adding-google-recaptcha-to-form
But there is no recaptcha selectable in the Submit Button Settings ➝ Spam Protection ➝ in the reCAPTCHA field. Only "None" is available.
I've also tried to use the Forms version from this comment: https://www.balbooa.com/index.php/commentID-13710
But it did not help. Currently I'm using Forms 2.4.3.4 and Joomla 5.4.9.
Please see screenshots.
Thanks in advance.