Eleventy Transform: how to specifiy where the images are stored?

[lexoyo]

Hello
I'm sorry if it's a documented question but I struggle with this for a day now
After following the instructions I can't get the images to be found on disk (I get the ENOENT: no such file or directory, stat 'content/assets/test.svg' )
My images are not in content/assets/ but in content/silex-published/assets/
My config is

{
    dir: {
      input: 'content',
      layouts: '_layouts',
      includes: '_includes',
      data: '_data',
      output: site.eleventyOutput,
    },
}

I don't manage to make the transform image plugin to look in a subfolder of content

  eleventyConfig.addPlugin(eleventyImageTransformPlugin, {
    extensions: "html",
    formats: ["avif", "jpeg"],
    defaultAttributes: {
      loading: "lazy",
      decoding: "async",
      sizes: "100vw",
    },
    //  urlPath: './silex-published/assets/', //  ====> doesn't do anything
  })

Any help will be a much appreciated, I know we are all very buisy, thank you !!