As a general consensus, I like to think of lag as something you can’t possibly stop unless your code/ build is optimised to prevent these performance issues.
In regards to detailed builds; textures, large number of part count, unions all cause lag. There isn’t any code that ultimately reduces lag, as there are so many parameters to considers for lag. It comes down to how you optimise your builds and understanding the cause of lag, before tackling it. So, no the rumoured tale of this so-called ‘anti-lag’ script is a baloney. Unfortunately.
Utilise the provided features such as StreamingEnabled, check if your parts are anchored (physics interfering), reduce the union count, limit part counts are all factors to reduce lag.
This is a very awesome topic about this: