• Sell them. This is the simplest option, and it can be a good way to get some extra gold. However, gold is not as important in Diablo 4 as it was in previous games, so this may not be the best use of Legendary items.
• Dismantle them. This will break down the item into rare crafting materials, which can be used to upgrade other gear or craft new Legendary items. This is a good option if you are looking to improve your character's gear or if you want to try your hand at crafting.
• Extract the Aspect. This is a new feature in Diablo 4 that allows players to extract the Legendary power from an item and place it on another item. This can be a great way to create powerful builds, but it does require some planning and resources.

Ultimately, the best way to use Legendary items that you don't need will depend on your individual playstyle and goals. If you are looking for the most efficient way to improve your character, then dismantling them for crafting materials is probably the best option. However, if you are looking to experiment with different builds or create something truly unique, then extracting the Aspect may be a better choice.

Here is a table summarizing the different options for dealing with unwanted Legendary items in Diablo 4:

I hope this helps!