Ubuntu - Copy large number of files easily to Android Phone

Situation:

The MTP protocol for transferring files to and from an Android Phone is utter garbage, especially when transferring a large number of files (like your Music collection for the first time - on my Google Pixel). The connection inevitably fails in the middle of the transfer, which is slow to boot.

Solution:

USB tether your phone to your computer (read http://abidmujtaba.blogspot.com/2017/07/ubuntu-usb-tethering-with-google-pixel.html if you get stuck). You don't even need internet pass-through, just an IP Address (so you can use sudo dhclient usb0 instead of sudo dhcpcd usb0 if you are using the terminal).

Next follow http://abidmujtaba.blogspot.com/2017/07/ubuntu-ssh-in-to-android-phone-google.html to set up an ssh connection. Once you have that you are home free.

I use lftp over ssh to copy all the files I want. I even have a simple lftp bookmark set up:

pixel sftp://abid:xx@pixel

where my ssh config section is titled "pixel" and the password "xx" is just a red-herring since ssh is configured to use an RSA key for authentication. This bookmark allows me to access my phone's files using a simple lftp pixel.