How to dynamically pass contextual filter to a block view without changing view settings
You have a task: 


  " I want site admins to be able to change the featured artist ( node id ) but I don't want them to have access to the views interface )"


and it seems you already decided to use specific solution:


  pass the the node id via the blocks interface


Don't do that. That's pretty weird and unneeded. Easier options are:


Draggable Views and show only first one
Use "sticky" or some other field to mark promoted artists (random order, limit 1 in case more than one is selected)