[QianyuLi]

AVC is H.264 and is the default old video codec,
if supported is preferible always enable VP9 and/or HEVC codec

the reason is that an AVC stream to achieve the same video quality of VP9/HEVC require more bitrate
the higher bitrate in a AVC stream not means better images, means that AVC has worse video compression



if instead you want choose a stream with lower bitrate instead higher bitrate,
then you have to change bitrate settings in InputStream Adaptive addon
but remember that this will affect all addons that use this component

What he meant was that he wanted Netflix Add-On to provide similar functionality to that of this Microsoft Edge plugin.
That is, to force Netflix to provide AVC Main encoded video streams instead of AVC High video streams. And it seems that VP9 video streaming can be disabled by turning off VP9 within the Expert settings? I don't know, I'm not aware of Netflix offering VP9 video streaming.
Perhaps this edge browser plugin fork currently forces AVC Main video streaming to play properly.
I cannot determine the video quality of Netflix AVC Main and AVC High. There are some users who claim that AVC Main has higher picture quality. Of course I think the more advanced video encoding will win out over time.
Also have you continued to follow Netflix AV1 lately? Of course I know it requires DASH CBCS support and ISA doesn't support it yet.