idk if this is possible or not but can you try to make a 7k or 9k song?
I can possibly do that before v5.0 comes out! It's definitely not easy to add without degrading performance, though. I'm not sure if the game is laggy because I've heard that it is for some people.
I haven't really had any lag problems. I can let you know if there is any lag in the game if that helps.
