The Boeing 777x has huge wings to generate lift even to the point of having to have a hinge and being able to bend them.
Would it not be advantageous to have 2 wings like a biplane or one behind another? And what disadvantages would there be?
A biplane wing of a given span and chord has twice the area of a monoplane the same size and so can fly more slowly, or for a given flight speed can lift more weight. Alternatively, a biplane wing of the same area as a monoplane has lower span and chord, reducing the structural forces and allowing it to be lighter.
This is from Wikipedia so possibly not reliable.