Living with my sister and her bf is driving me insane

I’m living with my sister and her bf right now and honestly it’s getting unbearable. Every single day I have to hear her doing that baby voice to him, plus constant PDA and kissing, even when I’m literally in the room like I don’t exist. It annoys me so much, since she’s much older and her baby voice is just annoying to me.

I feel like I can’t even say anything because how do you tell a couple to stop acting like a couple? It’s so awkward. But it’s not just that, there’s been multiple times where I can hear them moaning, no matter where I am in the house. I’ve asked her to at least put on music, but she keeps saying I’m imagining it… which I’m NOT. Like why would I even want to imagine that??

It’s so hard to bring it up because she never takes it seriously, and her bf is the same. I genuinely don’t want to hear any of it. Meanwhile I’m over here lowering my own volume trying to be considerate, but they’re loud with talking, PDA, everything like it’s totally fine.

What am I even supposed to do in this situation