The thing that lags the most is the clouds effect. It’s a particle emitter with a size set to 500, and 200 rate, and also some sequences on the transparency and squash. The clouds go inward as well.
I’m not sure if this will help or not but Roblox made a Showcase that has a really cool black hole in it. It’s open source so you can go to the game page and get yourself a copy to edit in Studio.