There is no option for higher than 128 kbps AAC on YouTube (on site 720p+: 192 kbps).

YouTube encodes the audio stream to higher bitrates than 128 on videos with 720p and above, 4K sometimes seems to even have 256 kbps. Would be nice if your tool could select that.
OR, even better: Pull the equivalent higher Vorbis stream with the VP9/MKV.