I think the big issue here isn't exactly the DRS, although if the data in the game is saying the effect is same it sure doesn't feel like it. I think that's because unless you're driving a Ferrari right now you're just not going to beat them in straight line speed, especially in a My Team car. With a Red Bull you can pull along side with DRS but I've found if you don't use Overtake as well you may not get past them. Of course your AI strength setting has something to do with this also. The Ferrari's are really overpowered in the game currently, Red Bull isn't far behind. Which... in all honesty is what we're seeing on Sundays. The AI powered Ferrari's though; wow they're fast.
The one surprising thing to me is that these new cars are meant to follow closer and not have as much dirty air effect, but in the game it feels as if that dirty air effect is too strong. I was following Leclerc this morning driving as Verstappen at Australia and once you get behind you get bogged down pretty good in the turns. It's nice to feel that, but in a new generation of cars that aimed to eliminate that you'd think it wouldn't be as pronounced in the game.