Winamp was so slick. Lightweight, did one thing very well.
A modern version would probably be built on Electron, be a 500Mb download & require 8Gb RAM to just run (12Gb required if you want to change the skin).
I long for the days where things weren't so bloated.
An MP3 decoder is actually relatively tiny: https://github.com/lieff/minimp3 shows that it can be done in ~30KB of code. It's everything else around the player, such as the UI, that takes up the bulk of the size.