I know several players including myself who have all the cosmetics you can get from Illuminated chests and now they're stuck getting chests they can't use at all. I seen a couple ideas on how to fix this. Like having Eternals with all the cosmetics making a request to get their 2 monthly Illuminated chests changed to 2 Mythical chests. This makes the monthly bonus 1 Omega chest and 4 Mythical chests. Another idea I've seen was making a warning when you go to open Illuminated chests saying "You have all the cosmetics from this chest, opening this chest will result in a duplicate. Are you ok with this?" Just a thought.