Thank you sephore for pointing me in thie direction
strangely, it did not work when I added the
[build]
publishResources = false
to config.toml as mentioned in Easy way to serve responsive images with Hugo
but it did work when I added
[_build]
publishResources = false
(with an underscore as mentioned in https://gohugo.io/content-management/build-options/) to the index.html of my leaf bundle page
do you have an idea of what is the correct way of handling this and why the answer you pointed seems different than the documentation ?