Apple used to sell stuff that had “curated UIs”: few control, few functions, and excellent UX. I remember the cleanliness of the iPod vs the overfeatured and complicated competitors.
PS: if we include Sony's minidisk in the competion, the overall listening experience, especially the wired remote was just better. The digital walkman was still a better UX on the device side, except it has an even worse horrible PC experience and Sony barriers that made it a non starter.
The settings were usually pretty poor on those mp3 players, on mine you had a microphone mode, language, timezone, some shuffle configuration and that's pretty much it.
The iPod did look much much better and refined but in terms of simplicity, it's hard to beat the single play button of an mp3 player which doesn't know to do anything else. Those things were designed like appliance more than tech products.
I had one similar to those https://i.pinimg.com/originals/95/43/8b/95438b86a98370a741c2...
Those things really didn't have a single real feature beyond playing music and recording with a microphone in the settings (which nobody really used)
The screen and processing power was way too bad to do anything else anyways, even if they wanted to.