Every couple of years, I buy a used Sansa Clip+ from ebay to replace the previous one that suffered physical damage. I transfer over the 128GB/256GB sd card. Voila - entire music collection in the size of a box of matches, no need for data connections, or a working phone, or fumbling with a screen when I'm working out.

SHHHHHH!!!! Don't tell people that or pretty soon we won't be able to find them any more! ;)

Seriously though, seconded, but also install Rockbox: https://www.rockbox.org/