I guess you mean "idleassetsd"
Its a TVos process that is used to download the motion wallpapers available on Sonoma. Don't know if you can choose not to do the downloads, as the user does not control those.
Of course, you can choose not use the moving backgrounds, if you wish.
Maybe if you don't use those, they won't download. Or, it's a background process that happens until any available moving wallpapers are downloaded.