The only difference (besides the syntax) is, that the compiler guarantees that no user-overloaded operator is called when using is not null instead of != null (or is null instead of == null).

According to these explanations, there should be no difference between the two

But when I use the Unity engine with Json data
I see a functional difference that Is Not null doesn’t recognize Jason as empty, but it recognizes the same data as empty when I check it with !=

What is the reason for this?

Maybe there is something wrong, sorry (the translator is used)

I expected a null value to be detected with both conditions