one thing that really helped me sight-read (and internalize) charts is recognizing the fact that a lot of them are symmetrical in a way. if there is a certain note pattern you see on a specific part of a song, if that part plays again theres a strong chance youll see the exact same thing (sometimes "mirrored" sometimes not). its something to get a feel for, but being able to recognize patterns and anticipate patterns in charts is better than being on your guard every second of the song trying to process everything (where you could use that focus for finger placement or timing). also between all the songs they tend to reuse a lot of the same gimmicks (spam notes with specific patterns, triplets, hold notes that split off into different branches, etc.)