The error is in the launcher.visualelementsmanifest.xml.
The colors and icons are set there, but the file names for the icons are not correct.
Square150x150Logo = "Assets \ 150x150Logo.png"
Square70x70Logo = "Assets \ 70x70Logo.png"
150x150Logo.png and 70x70Logo.png do not exist, only additional versions for different scales and contrast.
I have created a copy of the 2 different sizes, each of the highest scaled version. These were then renamed, so that they will be found.
then I change only once the size of the tile and the icon was displayed.