I agree with HS, above, that fundamentally your concept/mental image of how "attack" the ball is faulty.
Don't think about "brushing the ball". That is really a poor way to explain what needs to be done. It creates a mental image implying that you are actually trying to spin the ball the way you might roll a plate on its edge with your hand. And, obviously, rolling the racket over the ball-- also drives it downward into the net.
So, as HS also mentions, you need to hit THROUGH the ball. Your racket face should be pretty much vertical to the plane of the court and traveling in the direction you want to send the ball. The racket head should DRIVE THROUGH the ball in a fairly straight path from low to high. The angle of the path, shallow or steep, will determine the amount of spin.
The less steep the angle the more force goes to forward momentum and less to spin. The greater the angle, the more spin and less forward momentun-- until at a certain point the spin becomes counter-productive.
Keep practicing.
So, watch the ball, imagine the line your racket needs to take through the ball, and drive the racket smoothly, yet forcefully, through the ball. And forget all thet "brushing" stuff.