Lags more than normal when I change parameters like: chunk, shaders

[Strondezin]

My game lags when I change the chunk size (even if it's down)
and it takes time to load when I change shaders. Furthermore, I see some bugs in a Shader called Kappa, like blocks with lighting that have nothing to do with the environment. Sometimes it's low quality when I'm with Kappa. (Kappa Shaders v5.2)