Hey. So a common misconception is that advertisements gets you concurrent players automatically, that’s not the case. It depends on your gameplay, and how attractive your game is to the player demographic playing it.
As for CTR, always aim to be at least 1.00% no matter the size of your game as this will help you maximize bringing in players and getting the back for your buck.
Make sure your advertisement targets the age demographic or player your looking to bring to your game and that will help you harness the most loyal, and henceforward, concurrent players.