ClosedFTP account for child domain

Hello, we can add a child domain (subdomain) from the administration area of ​​a website we added. So can we create a special ftp account for this subdomain? (For example, user can only see files belonging to sub.example.com in ftp account)

I couldn’t do that, so I’m adding subdomains like adding a new website. (From the menu Websites >> Create Website) I also add an A record in the sub name.

In this way, the subdomain is treated like a completely different domain name and I can create a private ftp account.

But I don’t know if this method will cause problems or not. (Maybe there will be problems with the updates.) Do you think there will be a problem?

Add subdomain as a main domain and it will act and perform all functions like a main domain can create FTP and all