I agree that bottles usually have a neck (except in weird cases where someone took what was once a bottle and removed the neck while keeping the same function) and that jars usually don’t.
But I can think of things that are jar-shaped that we don’t call jars. On the ground in front of me is my Lays Stax, which are in neck-less cylindrical container. But I would never call it a jar of chips. Even though it is plastic, I think I’d call it a “can.” I also have a container of sugar that has a very small neck, but is mostly cylindrical. It’s about twice as wide as the can I mentioned earlier, and a bit taller. It has a screw on lid, unlike the “can.”
It doesn’t seem to be a jar or a bottle. We just call it a container. It seems too big to be a bottle.