This is rough. But at least Suzuka isn't completely oblivious—she knows damn well that even though she's the girlfriend, Ria is the one Haruka's more attracted to. I'm glad she's willing to fight for her spot. What gets me though is that she's already resigned herself to being worse than Ria, and that insecurity's pushing her into using these unnecessary tactics instead of just trusting what she brings to the table.
I see the angle Suzuka's going for, and sure, it adds spice to the story. But trying to make Haruka jealous? That's gonna blow up in her face. Anything that happens from here basically just helps Ria get closer to Haruka. He's not gonna be cool with some dude on the same committee as Suzuka having feelings for her—that kind of closeness happening outside his line of sight is gonna strain their relationship, and Ria becomes the rebound he vents to. And if he finds out the whole thing was a setup? Then Suzuka loses whatever trust she had left, Haruka's resentment shifts squarely onto her, and she handed Ria the opening on a silver platter. Even in the best case where Haruka never finds out, the jealousy still eats at him, makes him pull away, and Ria's right there waiting. It's a lose-lose and I can see every path leads back to Ria.
Thanks for the translation!