In my experience, while osu is a good warm up it’s not a substitute for a 3d aim trainer. Unless you are using mcosu with some modifications - using the fps mod and making the circle size smaller, among other things - the aim in osu doesn’t transfer one to one to shooters. While it certainly helps getting the hand movements like the flicks and such ready, 2d just isn’t the same as 3d since you can’t even map the sens to be the same, its kind of impossible actually.