Greasy Fork is available in English.
auto-selects 1080p (or highest available quality) instead of the recent default 720p
this script is also integrated in 9anime Bingewatcher+ (which has many extra features)
9anime Auto-1080p Select (Vidstream/Mcloud)
About
this script will automatically select 1080p (or highest available quality), instead of the default 720p, on Vidcloud and Mcloud video hosts
Background
Lately (past few months), 9anime has made it so when loading a video page, it automatically defaults to 720p. If someone happens to notice this change, they could manually set it to 1080p. However, this change is not saved, which means having to remember to re-select 1080p on every single video.
This was a recent 9anime change, since it used to remember your choice in a cookie. I'm sure this change was done to lower bandwidth usage (perhaps due to increased views during quarantine), especially among viewers who probably wouldn't even notice the difference in quality in the first place.
But, if you're able to notice the quality difference, this script should be useful.