Hi @dlyakovetsky!
The S3 Uploader component is considered a legacy component, and we are in the process of deprecating some of our legacy components. The newer File Upload, File Button, and File Dropzone components supersede the S3 Uploader component with more functionality and better styling controls. Since these are generic upload components, it does require some configuration to hook up to your S3 bucket (namely, creating a query using your S3 resource and setting it up to read the data from the upload widget).
However, we understand that you may rely on the legacy component and may want to continue using it -- in which case, you can bring back deprecated components by toggling a setting. Click on your user icon on the top right from the app listing page, click "Settings", click "Beta" (https://[your-subdomain].retool.com/settings/beta), and toggle on the "Deprecated components" setting.
David