Template framework is a single home structure, and Page Builder is like a room inside. Each room can look different, but they still will be inside that home.
it's a Layout Manager for module positions and to maintain Header, logo, color, fonts.
Page Builder is a component - it means that operates only in the component area, like any other component. It has its own add-ons like: Tab, Accordion, Pricing Table, Team, Testimonial etc. which you can place on the Page Layout.
My suggestion is Install Helix Ultimate quickstart pack. You can test both Helix Ultimate Framework and SP Page Builder. It's totally free. Follow their documentation it's too easy to maintain.