The selection of endgames studies for studying not an easy task.
I prefer those positions which contain practical technique, strategies, and calculation which (however hidden) give my brain a workout leading to further understanding as opposed to studies whose solutions last far too many moves and whose computer-like nature defy any logic I can generate.
A wonderful starting book for those dipping their toes in the water is Endgame Magic, by John Beasley & Timothy Whitworth.
I hate end game study friends