Twitch affiliate here! Do you have any logs from Twitch Inspector from recent streams, especially from when you first noticed the audio issues? That would give a more in-depth look as to whether it's a network issue, ingest issue, bitrate issue, etc.
Also, which streaming software do you currently use? OBS Studio or one of its branded flavors? And what are your streaming settings in your software?
If you could, please attach a screenshot of a current internet speed test, your streaming software settings (most importantly is encoding, streaming & network/connection settings. blur any identifying/personal info like IP, DNS, Stream key, etc), and most recent log from Twitch Inspector (one where you noticed audio issues would be best).
