sftp vs ftps, securing SSH and virtual users vsftpd

I wouldn't say FTPS is deprecated. It still is a viable option for secure file transfer.

The way you describe your situation makes it sound as if FTPS would be the most suitable solution for the problem you are trying to solve, but you fear it is old fashioned.

I wouldn't worry about that. If FTPS solves your problem, go for it.

A third option you could consider is WebDAV. Like with FTP, adding virtual user accounts can be very easy.

FTPS is not atall deprecated. The implicit method of negotiation is. It can be very secure if configured correctly, and wont require you to enable password authentication within sshd