GTA V was available for free on Epic’s Game store recently and so I snatched a copy. There is the option to listen to your own music as one of the radio stations. Unfortunately, GTA V does not ask you for a location of your music. Instead it expects that you copy the files you want to listen to to a folder in your user directory. Now, although my collection isn’t insanely huge, I still do not want to copy 30 GB of files. There is a better way though, one that I have not found on any other site: A Junction Point.
This is a symbolic link from where GTA V expects the music file to where they are actually located on your computer. This way you are not wasting any space and changes you make to your collection are immediately reflected in the game.
mklink /J "C:\Users\<Your Username>\Documents\Rockstar Games\GTA V\User Music" D:\Music
Remember to use quotes around paths that contain spaces.