Syncthing is a continuous file synchronization program. It synchronizes files between two or more computers in real time, safely protected from prying eyes. Your data is your data alone and you deserve to choose where it is stored, whether it is shared with some third party, and how it’s transmitted over the internet.
I think ive posted this a long time ago and mentioning it again because of how useful it is. Many here use various ways to transfer files there are several apps out there availiable. I find this one best for my needs and you might as well especially if you have multiple boxes you take care of.
Give it a look, its free and very robust. Easy once you dive in. Google play has 2 versions the original and a forked version thats suposed to be better. I will be looking at it later tonight.
My general setup is on my pc I keep dedicated folders for android files/apps, pictures for wolf etc and many m3u’s and tivimate backup files.