

This might be a bit overkill for what you want but you could try using a selfhosted music server like navidrome and streaming to your phone. I use symfonium on on phone which can be configured to request the streamed music to be transcoded to a smaller size for streaming from mobile network or for caching it on your phones storage for offline listening.
Given that symfonium supports a lot of self hosted media providers from which to pull, you could also try sharing your music locally using samba. I’m not sure if the transcoding still works in that case though (it would obviously have to be done on your phone)
Depending on the specific model it is either an SSD or eMMC storage but you won’t be able to get to it without major disassembly of the device which includes removing the glued-on screen.
This surface is an absolute bitch to repair