The shopping cart software I personally use to create funnels, I got Thrivecart and Thrivecart Pro for a one time fee and it just keeps getting better.
Recently they added Learn and Learn+ to their offering making it a formidable bit of software. Easily able to handle any of your book funnel and upsell delivery all within 1 software.
2. Divi Theme
Divi is my landing page builder of choice.
Does come with a learning curve but once you get used to it you will wonder how you ever did without it.