`var` in Java is local for a reason. In most contexts I can think of the variable either was created above or was passed in as a parameter/object field. Unless you set it from a weirdly named creation pattern/function.

Regarding records, you never had someone update a POJO, add a field, and forget to update equals and hashCode?

Sealed classes are great for everything parsing/validation, in data modelling. They're not a solution for behavior polimorphism, but I don't think they were supposed to.