I also own the Soundcore A30s, but I've found the active noise cancellation to be fairly underwhelming - and certainly nowhere near the level of Apple AirPods Pro or Sony's WH-1000 series. To be honest, I expected much better ANC performance. As for side-sleeping, that's probably a very personal thing, but I don't find them comfortable enough for it. They still protrude a little too much and tend to press into my ear when lying on my side. That said, they're perfectly serviceable as a backup set of earbuds. With ANC enabled, they do a reasonable job of taking the edge off airport and travel noise, making the world a little quieter. They help, but they're not in the same league as the noise-cancelling performance offered by Apple or Sony.