Owncloud infinite scale is a rewrite of owncloud(=nextcloud) in go, it supports local, nfs and S3 mounts. Change the smb share to nfs and it might fit you
Disadvantages are:
All the plugins need to be rewritten, so if you need some extra feature, it’s going to be missing
They got acquired by a company that sells an expensive alternative for corporations (RIP? Who is paying millions to maintain a free alternative/competitor?)
Documentation is inferior, community is much smaller