Has there been an audio original which was uploaded, or were there overdups over the Suno track, or additional mastering? It sounds better (both musically and also the sound quality) than what Suno v5 can do from my experience.

Ok, the sound of the piano in track 2 is pretty typical for Suno, and there is some aliasing on the hi-hat, but the overall quality is still better than what Suno directly generates.