How do I remove the white background from app icons?!

[Android Central Question]

I have a Samsung S9+ with the latest update downloaded (as of 6th March 2019), but since the previous two updates many of
my app icons have an ugly white background. Internet searches show this super easy option of Display> Icon etc but that simply doesn't exist on my settings. I want transparent backgrounds for my app icons, I'm sure I'm being stupid as I've never had to post such a question before but hth to I get the app icons looking smooth and nice like before without that horrible white background?

 

[lucianus_luciferus]

switch to the default theme. see if it helps.