Losing my will to play support.

So, I've had a single rank 6 token for Leona for about 2 or so weeks now. And recently, I've gotten back into playing her, and I'm doing well. But no matter how hard I try, it feels like it's near impossible to get an S- or higher on her or any supports I play. I don't know what RNG god I have to impress to earn her 2nd rank 6 token but it's so demoralising when I think I've done so well and receive an A+ or lower every time. I just want to know what else I have to do. I know dying pretty much ruins your chances of that S, but it's dumb especially when you're the reason your team won, with calls or picks or all-ins.