Is there any study about user preferences icon placement? Do users expect it to be on the left/right side of the top bar?
Reading Gravity and Strong Fallow Areas
There's a technical reason for putting icons, avatars, and other secondary UI element in the top right of the screen, at least for websites in a left-to-right languages.
See my answer to this question - What is the best location to place an identity context control (avatar, name, sign out button)
The way that we read and scan pages makes certain areas better or worse locations for primary and secondary UI elements.