How can I efficiently move 40+GByte of mp3 data to my phone?

My entire music library is sitting on a server that I access through SSH (could be setup for HTTP) and I would like to copy it to my Xioami Mi A1 (running Nougat). What would be the best way to accomplish this without using an SD card? I installed Termux, and an rsync client, but: * I don't know the location of where I should download too, and * there seems to be a permission issue anywhere outside Termux's home directory ('whoami' reports my user credentials as "u0_a###") I would like to transfer the music to the "proper" directory (not just the downloads directory). With 50+G of unused storage space, I'd really like to make use of it.