Can I copy a section in the page builder instead of building it again?

Yes. In the page builder, each section in the left-hand list has small buttons next to it:

• ⧉ (Duplicate section) makes an exact copy just below.
• ↑ and ↓ move a section, or drag it by its handle.
• ✕ deletes it.

After duplicating, click the copy to edit its text and images. To tell the two apart in the list, click the section name at the top of its edit panel and rename it. This only changes the label you see, not the section itself.

Click Save in the top bar when you're done.