Android icons can't be changed?

I have a Huawei mate 10 lite and I'm now bothered by gray squares behind icons of apps that are not square. I tried to change it with the nova launcher, but nothing has changed. Anyone have any idea?

If you use the Nova Launcher, you just have to go to the icon settings then change the icon and select the same again, then I think the corners go away. Somehow that's how I did it back then. Changing the settings somehow had no effect.

Otherwise you can try to change the appearance in the settings.

Simply download an icon pack from the playstore.