Comment by mickael-kerjean

I'm the author of another option (https://github.com/mickael-kerjean/filestash) which has a S3 gateway that expose itself as a S3 server but is just a proxy that forward your S3 call onto anything else like SFTP, local FS, FTP, NFS, SMB, IPFS, Sharepoint, Azure, git repo, Dropbox, Google Drive, another S3, ... it's entirely stateless and act as a proxy translating S3 call onto whatever you have connected in the other end