Copper ore is found after the nether ores in the creative inventory, not after the ores of the upper world / among the ores of the upper world.
Steps to Reproduce:
- Change the game mode to creative.
- Open your creative inventory.
- Find copper in the "nature" tab or in the "all" tab.
Copper ore is in after the ores of the nether world.
Copper ore will be among the ores of the upper world.