How to snag customers if what your company does is too hard to explain [on hold]

Some businesses can easily explain themselves:

• "Buy cars at low prices!"
• "The front-end framework for Rickrolling!"
• "Our JUULs are too cool for the pool!"

On the other hand, my website's service is a long, complex process that I can't sum up into a slogan. It takes several paragraphs of explanation for readers to get the gist of "what we do," "how it works," "why choose us," etc. Nobody likes a wall of text on the homepage. How do I get conversions when people have super-short attention spans and won't sit down to read a long article? How do I compete with other sites that have clear value propositions?