You can extract aspect from legendary items and they will be stored in Consumables tab in your inventory. Doing this destroys the item. From there you can imprint it on a other item when needed but you won’t be able to extract it again. I haven’t tried imprint new apsect on another legendary item yet. If it’s possible I would assume it would overwrite the existing one. So you’d lose it.

I also use Helltides website for mystery chests and mapgenie for the rest.Link to Diablo 4 Mapgenie.