“I’m religious and find it hard to imagine that God would create such an immense playground/laboratory, and not fill it with more creatures to entertain himself.”
God’s ways are not our ways. You are anthropomorphizing God, a heresy.
Trying to imagine God’s thoughts and intentions is as old as man’s existence, and is present throughout the Bible and Christian literature. I reject your silly attempt at judgement, and remind you that you are not qualified to speak for him.