The last post I can find is from 2017 where people reported having their carry-on bags weighed and not to exceed 7KG/15lbs. Is that still the case in Y and PE?

Most carry-ons weigh 9lb or 10lb empty (mine is 6lb) but that does not give you much for the actual contents. If they only care about total weight of the aircraft, it seems a bit mean if you don't have any checked bags!