I preferred a customized photo for my phone, but you can also design a case all your own from different background colors, text, pictures, and layouts. (apocketfulofpolkadots.com)
See the Color Tool to determine if certain foreground colors used for typography meet accessibility standards against different background colors. (material.io)
Whether it's something small like changing the size of notification text, or major changes such as using different background colors for Quick Settings, OEM skins can completely ruin one of the most central menus in Android. (android.gadgethacks.com)