I remember our member posted awhile ago how to change display time colour or sizes
Locate the setting apply or swipe down from the top untill you see icon search
Type the words lock screen
It will bring you to lock agreen and AOD
See picture
At bottom tab on edit lock screen
Tap on that time
It will prompted you on different option. Select what suit you then click done
Sorry getting back on this so late as I did not have One UI 7 so I can't tell but now here I am. Hope you try it out
