I think double-ended usb drives are a thing, you could probably attach one of those for storage so that you can easily add music
@unascribed @chao @xenon is there no chance with alternative fs, or a Ο4 connected to a SSD & also works as a server, connected to a working Ο4 screen?
@_microbe101 anything is possible with an alternative fs assuming the usb drive can do it, but i suspect the micro USB and USB sides are connected to the same places on the board precluding any of this from being feasible
and communication over a filesystem without any form of notification of change or a way to send interrupts is gonna be slow as hell
@_microbe101 and for the Pi4 solution I believe you've just reinvented the NAS
@unascribed thanks for your input, NAS was a solution what a friend of mine does, the kernel change sounds not a good idea (slow, no response notification)
but i'll learn more about that. 
@xj9 @unascribed @_microbe101 hmmmmmmmm that looks shiney.
@_microbe101 @unascribed ...I've been thinking about a Pi Zero MP3 player for a bit.
I've considered solutions to the "music transfer" problem.
One is to use the USB-OTG feature of the PiZero:
https://magpi.raspberrypi.org/articles/pi-zero-w-smart-usb-flash-drive
Another is a USB direct transfer cable, called "host-to-host":
https://www.linuxquestions.org/questions/linux-hardware-18/usb-host-to-host-cable-which-one-575469/
And a third would be a networked option, like a Samba share over wifi.