In the sleep menu option a way to signal your going to bed now would be useful, I already have several nights were I went to bed late/early I discovered there was nothing recorded when I later got out of bed.
also useful would be mono and dichromatic night time themes that are devoid of the color blue. so Red, Green and yellow are your colors of interest here.
Sleep measurement is extremely inaccurate. Improve software to it accurately measures when you are sleeping or at least add a feature that lets you indicate when you are going to bed so it doesn’t count sitting still as sleep time. Currently it way over estimates sleep time.