[rmrector]

And of course there I go complaining without the necessary counterpoint: I am a big fan of Kodi and do appreciate all the effort, time, and expertise Team Kodi has put in to make Kodi the best in class and their stewardship with continual improvements and new features over the years. I am here contributing my own time and effort in the ways that I can because Kodi is great and I appreciate it.

I am having an issue with the movie set artwork.
...
EDIT: I managed to solve the issue by using the "Remove artwork for media type" option in Artwork Beef and removing the art for the sets and then rescanning.

Yeah, artwork for movie sets can be troublesome, and that is the best way to deal with it for now. Artwork Beef should be better about catching this for new movies and movie sets added, but it may still miss some items.
 

i miss the “Automatically preload local video / music library artwork to Kodi texture cache” feature in newest version?
Is the feature dropped?

Nope, it is on the "Advanced" tab of the add-on settings, where it's always been. Make sure you actually have the newest version installed: 0.22.0.