Yes, Drag, Drop & Upload Files to Amazon S3 app is supported for experience users. You will need to configure basic settings in your org to use it.

  1. Enable Digital Experience - 
    1. Enable and setup Digital Experience in Salesforce org if not already done.
  2. Create new button for community and edit the URL of a custom button to similar to that we've created during the configuration (step 4)of the Drag, Drop & Upload app in our org
    1. The existing URL of the custom button is -  /apex/DragDropToCloud__DragDropUploader?parent_id={!Account.Id} 
    2. For the experience, URL should be - yourExperienceBaseURL/apex/DragDropToCloud__DragDropUploader?parent_id={!Account.Id}
    3. yourExperienceBaseURL- put here your experience site base URL
  3. Edit AWS bucket CORS to include community URL - refer How to setup CORS?
    1. Default CORS without community URL -
    2. For experience use: We have to set CORS like:
  4. Assign Drag, Drop & Upload Files to Amazon S3 app license to the required experienceusers - 
    1. Go to Setup > Installed Packages > Drag, Drop & Upload Files to Amazon S3 > click on Manage Licenses and  add required experience Users.
  5. Create permission set and assign to the experience user -  
    1. Go to Setup > Permission set > Create new permission set.
    2. Give Read / Create / Edit / Delete access to the Cloud Document object and all field permissions and save.
  6.  Login to experience as user and test changes -