Kasa has seemingly always had an issue where custom icons are reduced to very poor quality, regardless of the images you use.
For the past few versions of Kasa, this could be fixed by replacing the files in your filesystem after Kasa had compressed them, as described here: https://community.tp-link.com/en/home/forum/topic/159363
With the latest version though (I'm using v 2.20.0 build 918), this doesn't seem to work the same. Following the same procedure, I get a good quality icon in the device settings screen (and I can even replace the background image for the device screen), but the main menu where all the devices are listed still has a blurry / low resolution icon.
Has anyone figured out a new way around this? Will we ever get a version of Kasa that doesn't compress custom icons to 5 pixels by 5 pixels?