Didn’t know that YouTube had 160kbps audio… I checked a auto-generated upload on yt-dlp, and while it had an Opus stream, all of the audio streams were encoded at 128kbps.
Both Opus and properly-encoded AAC audio should be virtually indistinguishable from the original source, but I do believe that Opus performs slightly worse in blind ABX testing. Again, you’d barely be able to tell the difference, so sound quality is basically the same.
(As for encoding, I believe that YouTube uses the source audio if it’s already encoded as AAC, which most video editors do by default, and music distributors send the same lossless source to YouTube as they do to Spotify, so I don’t think re-encoding will make a difference)