Most of Sonic's abilities even hitting him are useless thanks to Yu's Invulnerablility. And by the grace of god Sonic does manage to harm him, he has several mirror abilities to "No u" it back, has regen (depending on the Persona) and can heal himself independent of a Persona. And on the Topic of Sonic having Invulnerablility himself, a good ol scaling and Samsara/Die For Me! (which are instant kills) Should cover it.
Hyper Sonic is already above Super who stomped a casual low 2-C being, so I doubt the dude having a AP advantage, idk about the rest
I'm assuming this is World Arcana Yu so he also not only stomped a Low 2-C but is above several other Low 2-Cs such as The Velvet Room Attendants and Phantom Thieves, SEES/Shadow Operatives, and Investigation Team separately sans their own Wild Card members. All of them are Low 2-C. He's also already fought 2 other Low 2-Cs and beat them with Izanagi no Okami, albeit with Makoto Yuki.