According PureDhamma (as far as i understood and simplifying alot) underlying Arya Jhana there must be a very deep understanding of Tilakhanna AND such Arya Jhana should be attained not by focusing on a somewhat “material” point as breathing, it should be attained by focusing on a concept.
However to focus on a concept might not be suited for some gatis; that’s why i prone the practice of at least two procedures, one conceptual (even if difficult in the beginning) and the other non-conceptual (breathing or else) to attain Jhana.
But of course non-conceptual procedures like focusing on breathing should be accompanied by alot of contemplation (bhavana) then the Jhanas obtained through i.e. breathing can be considered Arya Jhanas – isn’t so ? For you can’t correctly and longly focus on breathing if your mind isn’t enough purified by deep undeerstanding !
Third hypothesis – this more related to the magga phala concept – by living ethically and alot of study one can also evolve…however this would be another subject…
As for rapture it’s ok as much as one doesn’t become dependent on it.