Are hard jhanas attainable outside of a retreat?

Recently back from a short 3-day retreat, of which the first day was dedicated to anapanasati. I experienced some really cool states through the ten-odd hours of exclusively focusing on breath sensations at the nostril area.

I've been reading a lot about going deep in this route. Shaila Catherine has written an excellent book about entering the deep hard jhanas through anapanasati, but at the end of the instructions, she adds a note that for most people, a retreat of about a month or more would be required to get into these hard jhanas.

Stephen Snyder, another teacher of hard jhanas, has mentioned in an AMA here that it would be quite extraordinary to attain the jhanas he teaches through practice at home.

I find all this quite discouraging. Should I give up my quest already? Has anyone here actually got into the hard jhanas without setting aside many weeks for retreat?

P.S: I have accessed the jhanas of Brasington (as explained in his book 'Right Concentration',) and I'm very grateful to him and the book, but I somehow get a feeling that 'there must be more to jhanas than this' when doing those jhanas.