Arguably you should forget the pre-launch landing page at all and just ship the thing.

Beta users rarely mean much of anything if you're trying to build a real, profitable business.

That being said, your job is to literally sell people on your product. People don't buy features...they buy painkillers. Focus on the pain your product is solving and use that to convince/entice people.

Happy to hop on a call and talk through what this means and how to do this specifically for your product.