Unable to change Contacts background color on iPhone 16 after iOS 26 update

I'm sorry, but no one here can fix that. This is a user to user support forum and Apple does not participate here. They would not see your statement regarding fixing it.

I noticed that change when i responded to another thread about font color in Contacts, I just wonder if it had something to do with the ability to create posters. I cannot really say. I've not taken time to review, since I've not experienced an issue with reading anything in Contacts, however I don't usually put a great deal of text in Notes. I'm not saying this is not significant to you, but to start with you can either contact Apple Support Official Apple Support or you can use the feedback link to let them know your thoughts here, Feedback - iPhone - Apple

I tried editing one of my contacts and surprisingly when you tap Edit it turns to a white background for you to edit it and then when you save it, it changes color.

Nope. This is left to we volunteer users. They handle the real support page.