Sony still makes very nice players - under the "walkman" brand no less. https://electronics.sony.com/audio/walkman-digital-recorders... . Probably too pricey for a 10-y-old child, but you might be able to find a used one on ebay?
Both are compatible with rockbox, so if you install that you can be sure they aren't running android: https://www.rockbox.org/
That model looks a lot like what the iPod nano did.