Hi Sancucay,
Here, I am doing exactly what you are looking for, so it is clearly doable, no doubt. To configure it is one thing, to keep it running smoothly is another. If someone else do it all for you, you will not understand your setup as well and so you risk ending up in trouble when something will require attention.
Part of the design you must not forget is backups. No matter how solid a single FreeNAS server can be, it is and remains a single server so a single point of failure. You must have a backup strategy. Here, I do ZFS replication to a second FreeNAS over VPN, hundreds of Km away from my main server. That way, no single physical incident like fire can take both servers down.
People are used to think that clouds are magically always On and 100% reliable. If you are about to rely on your private Cloud with such an expectation, you must master it from A to Z (and also get real about that because even Amazon and other Cloud providers lost data in the past...).
As a cloud solution, I use Nextcloud. I chose not to use the plugin from FreeNAS and I run it from a Docker host in my ESXi server next to FreeNAS. The storage is mounted over NFS from FreeNAS to the Docker host and that host re-map it inside the container.
To secure everything, I have a pfSense firewall running HAProxy and a Q-Radar Community Edition for security monitoring.
To design a strong, secure and reliable private cloud is doable, but requires you to master a lot of different concepts, technologies and processes.