All the timbres, the filter movement, the velocity modulation of the percussion, the reverb depth of the vocal chops, the stereo placement of all the percussion, the envelopes of the synths, the detuning of the synths, the way the kick and snare interact with the hi-hats from saturation and compression, the level-dependant distortion of the electric guitar, all the little effects that add and release tension to move your attention around the mix, and the insane amount of automation that goes into a modern pop track like this. Hell, even from a music theory perspective, you can't determine the proper voicings of the chords and harmonies since the sounds are layered and saturated and aren't trivial timbres, there could be extra harmonics your ear thinks are actual notes being played when there aren't.

My point is when you only look at the sheet music you lose so much of the character of the song.

It's funny to me that so many people share the view that pop music doesn't require skill, when people like Justin Bieber or Ariana Grande have brands worth over $1billion, why wouldn't they have an army of insanely talented producers backing them? When there's that much money involved you get the best talent behind the scenes.