Comment by mickael-kerjean

That's one of the features of Filestash (Disclaimer: I made it). You connect whatever storage, give it the authorisation you want (eg: ls, cat, mkdir, rm, mv, save), and through the SFTP gateway you can mount in your FS and get full auditability, with the audit trail being tamper proof, traceable, timestamped and non-repudiable

  link:
  https://www.filestash.app/ 
  https://github.com/mickael-kerjean/filestash