So I tried to stream on twitch through amd software today and I couldnt find where to change the encoder.
Nobody wants to stream in AVC so if you want people to use your software I recommend to add it.
If I consider start streaming I will download OBS for AV1.
From the top Record & Stream tab > Record:
Video Encoding Type = HEVC
That setting doesn't apply to the Streaming side of things? (I ask because I've never streamed).