SPFx ListView CommandSet docx to Pdf

Question

I try to convert a selected Word document (docx) in a SharePoint-Online list with the Graph Api (MSGraphClientV3) into an Pdf document. I can successfully upload the seleted document to my One-Drive

const apiUrl: string = `/me/drive/root:/${file.name}:/content`;
const resp = await this.client.api(apiUrl).put(file);

But when I try to convert the document with

 const options = {
    headers: {
      'Content-Type': 'application/pdf',
    },
  };

  const blob = await this.client
    .api(`/me/drive/items/${fileID}/content?format=pdf`)
    .headers(options.headers)
    .responseType('blob')
    .get();

I always get: "Resource not found"

The fileID is correct as I can download the file with:

const apiUrl = `/me/drive/items/${fileID}`;
        
this.client.api(apiUrl).get()

Api permissions of my package-solution.json:

"webApiPermissionRequests": [
  {
    "resource": "Microsoft Graph",
    "scope": "Files.ReadWrite"
  }
]

Permission request is approved through SharePoint-Admin Site. The Api call should respond with a 302 Found response redirecting to a pre-authenticated download URL for the converted file.

I do not want to use Flow or an Azure function to do the conversion. Spec is here.

What am I missing?

Thanks, Ronny