Yeah, all the modern kids say to hit with more topspin and harder to win.
I've found winning has little to do with hitting hard. Winning has everything to do with hitting shots that bother your opponent. Two very different things.
Like my normal second serve, swung like I'm hitting a 125 mph first serve (which I cannot do when I pronate to hit flat), curves a certain amount and oblongs and phizzes tru the air. Oftentimes, if I back off the rackethead speed a touch, that serve is TOUGHER to return because the ball goes a hair slower, and the curving effect takes precedence over the ball speed, making the returner have to adjust much farther to take the ball in his strikezone.
Same sometimes for my first flat. I can pound it maybe 115 pretty often and IN, but with good placement sometimes needed, if I back off to 105, the placement hugs the sidelines and goes IN much more often.
If I crush my hardest forehand topspinners, sometimes the opposition get's "UP" for my game and plays better than his normal self!
So quite oftentimes, playing within 85% of your normal game is plenty good enough to play within your own level.