Not necessarily, since ring finger usage isn't strength. It's about how well you can move that finger independently relative to your other fingers, and in order to train that you need to use all fingers and slowly train finger independence. In other words, play the game more(as annoying as it sounds). The same applies to your middle index and thumb. I guess you could buy heavier switches for resistance training, but that's if you have the money and are willing to buy a whole separate keyboard for osu.