Chris,
I have been plagued by the same issue. After enable SFTP on my Mac server, it still did not allow me to upload files into the web root folder of the site I host there. Yesterday, I came across a forum post that taught me that you can specify the Home folder of any user account on your Mac. I tried it, and it works great! Here’s how:
1. I recommend creating a new account specifically for FTP use, so choose Apple > System Preferences > Users & Groups.
2. Click the Lock icon and enter your Mac admin credentials, if necessary.
3. Click the small plus sign (+) in the lower-left to add a new account.
4. For the account type, choose Standard. It may work with Sharing Only, but I haven’t tried it.
5. Make up an account name and password for FTP-ing, and click Create User.
6. Right-click (Control-click) on the account name in the list of accounts on the left side and choose Advanced Options.
7. Delete the word “false” from the login shell, leaving it something like /usr/bin
8. Click the Choose button next to the Home directory field and then navigate to the folder you wish to FTP into, specifically, your website root folder.
9. Click OK all the way out.

There were two other things you might have to do:

1. Change the folder permissions on your web root folder.
a. In Finder, navigate to your web root folder and click it once to select it.
b. Click File > Get Info. The Get Info pane opens. Near the bottom, you see Sharing & Permissions.
c. Click the Lock icon and enter your Mac admin credentials.
d. Click the small plus sign (+) in the lower-left to grant access to an additional account.
e. Select the FTP account that you created earlier.
f. Grant Read & Write privileges to that account.
g. Click the small gear icon (Settings) and choose Apply to enclosed items.
h. Close the Get Info pane.

2. Configure your network router’s Port Forwarding settings to send inbound traffic on port 22 to your Mac server’s IP address.

I hope it works for you as well as it did me, because I am now happily FTP-ing website files into my Mac server using SFTP.

However as the Mac only has 3 USB ports I started off connecting a good, powered USB 3.0 hub to one port, the Mac metal keyboard to the second and the external SSD drive to the powered hub. But it won’t boot (or even see) this drive. If I connect it direct to the Mac I have no problem.

So this left me with two SSD drives on two ports and the keyboard on the USB hub, but in this configuration, the Option (or any) of the startup keys are not recognised. But once the login screen appears, the keyboard is fully active.

This means if I need to use the keyboard at power up, I have to unplug the hub to plug the keyboard in, and then once I’ve passed this point, unplug the keyboard so I can plug the Hub in, and plug the keyboard back into the hub.

I know the keyboard has two USB ports, but some of my devices and memory sticks are too chunky to go under the keyboard, thus the need for the hub.

Am I missing something as surely this can’t be right.