I am trying to make an app icon 20 x 20 pixel dimension. I cannot get the icon to be sized this way. It gets blurry. I have used adobe express + illustrator. I have not been able to size it. It is a 400 x 400 dimension png. I want the proportion to be 20 x 20 without losing the clarity.
App Icon Dimension
You focus on your vector design tool for your icon, as noted in Prepare your artwork for export, so that you can export the vector data, and then use it with Icon Composer to fine tune it for Liquid Glass. With this approach, you won't need to worry about the numerous specific bitmap icon sizes that you may be familiar with from older iOS versions.
— Ed Ford, DTS Engineer