Yea, I have found by far the biggest effect for me (and I have to imagine most people) is the speakers / headphones, not the digital processing or even the audio converters.
headphones or speakers can't add the detail that mp3 (or streaming in whatever format) eliminates. Compare a CD and mp3 of the same track with a decent headphone (or a speaker) and you will hear that compression changes sounds.
but it all depends on what kind of music you listen to. For some of today's music even laptop speakers are enough 🤷
