How do I customize Home Screen icons on iOS 18.1.1?

Perhaps something here will help:

Customize apps and widgets on the iPhone Home Screen - Apple Support

Regards.

What app icons?

How are they different exactly?

Can you provide an example?

Do note, app developers can change their icons, is if you have a newer version on the iPad than on the iPhone it may be slightly different.

It may be you have a custom color applied on one device but not the other as suggested by varjak?

 If you wish to provide feedback to Apple, you can do so here:

Product Feedback - Apple

Regards.

I think I have the same problem. Was using dark mode before, and everything was great, but after update the icons got black background by default. When I changing to bright mode it looks normal, but then I can’t take it, or rather my eyes can’t look at white screen. It seriously disturbing. Apple please bring old feature back. Monochromatic option looks fancy on the promo picture but it’s not readable for me.

What kind of buttons do you mean?

Ive checked it, not the case. However somehow those icons have no longer black background in dark mode. I guess magic hapend.

Thx :)