Jwct sapphic ships and the rings they would get one another:
Yaz and Sammy: Ok so. I think that Yaz proposes. Sammy mentioned once or twice that she's always liked ruby engagement rings, and Yaz tucked that info away quick. I think Yaz gets her a gold ring with a nice, but sensible sized ruby. Sammy loves it. It's beautiful, but simple and won't get in her way.
Sammy doesn't propose, but she would undoubtedly want Yaz to have an engagement ring as well. She'd get her gold as well, but she'd do a classic diamond. Again, a sensible and practical size. They'd both have oval cut rings. Yaz would insist that she doesn't need one, but still feel giddy as fuck the second Sammy slides it on her finger.
For the actual wedding rings, I think they'd do dainty plain gold bands with each others names inscribed on the inside.
Soyona and Brooklynn: Look. Obviously this one is hypothetical, within the au of "Brooklynn or Soyona switch sides and do a full 180". Unless...
Soyona is proposing. No doubt about it. Not a big, romantic affair. Honestly the way I envision it best would be Soyona and Brooklynn drinking wine out on the balcony, and Soyona slides a box across the table to Brooklynn. No words, but just a look in her eyes that tells Brooklynn exactly what she means by the gesture. I should note, I think it would happen about three days post Soyona accidentally on purpose asking Brooklynn to marry her during sex. Brooklynn's answer would simply be a nod and a smirk as she slides the box back to Soyona and holds out her hand (obviously, her right hand. They aren't putting the ring on her prosthetic) for Soyona to slide the ring on.
Anyways. It's a white gold, diamond encrusted 4 carat sapphire cushion cut ring. Soyona genuinely thought about going bigger, but knew anything beyond 4 carats just wouldn't be practical for Brooklynn. She also def thought about going for an emerald, but sapphires are more durable, so ultimately she picked that.
I think that in an au where they get married, Brooklynn wouldn't even be shocked by the size and novelty of her ring. She'd be used to it by that point.
Soyona wouldn't want or feel the need for an engagement ring, but for her own wedding ring, she'd get herself a white gold diamond encrusted band. She'd get Brooklynn the same exact one, just slightly more dainty so that it goes well with and doesn't distract from her engagement ring.