MP3 320kbps is adequate. You don't "need" more. Of course you might want more (lossless or hi-res), but you don't need more.

Even with my Andromeda 2020 IEM (very sensitive and generally considered a very detailed IEM), I have zero problem listening to properly mastered music on YouTube. Even a simple live performance like Ed Sheeran's Tiny Desk Concert on YouTube can reveal the difference in detail / "resolution" between my gears, but none of them sound bad because I listen to a music video on YouTube.

If the music is poorly mastered, you will suffer though. Decent headphones / IEMs tend to dig out those problems.