All settings are stored in desktop-files in //~/.local/share/plasma_icons///:
find **Icon** and update it

Icon size: 24x24 is good enough. PyCharm puts PNG 128x128, BitWarden - PNG 512x512.

To find icon in snap:
  find /snap/bitwarden/ -name "icon.png"
  find /snap/bitwarden/ -name "*.png"