Two of my peace lilies. The one on the right came home in 2019, nearly lost it in early 2020, fully recovered by 2021. Bought the one on the left in 2022. They have been in very similar conditions for the last two+ years. But the one on the right has never regained the darker green leaf color. It turned much brighter green (I think it was getting too much direct light in that 2020/2021 time), and has stayed that way. Is there anything I can do to get it to go back? They are otherwise both happy and healthy.