I would argue (my opinion) - OOP smashes together state + behavior. The original reason for this was good: I.e the user of the class(object) should not need to

I would argue (my opinion) - OOP smashes together state + behavior. The original reason for this was good: I.e the user of the class(object) should not need to know ALL the internal details etc. Something like ECS (data-orientated). Very explicit separates DATA(state) and BEHAVIOR (System, Functions, Methods etc). For me at least it makes it easier and more reliable to "reason" and have a "mental model" about the big-complex system. If I know that for example in a game project ANYTHING with "gravity" is about the ONE Gravity-System(which runs 1x60 seconds in possible sep.thread) and that it Operates(change state) for ALL entities with the "Mass + Pos Components."