I think you fault of understanding Dhamma comes from modern thinking as technology, for example you are looking for a phone that will connect you to “Nibbana” but there is no such thing and rather than putting all the focus on trying to find the right “method” you should stick to enhancing your mental factors as explained for example in Satipatthana, what matters is what you do with your mind, how you understand things with proper view and how do you deal with attachments. You can get rid of attachments without even a second of meditation with the right guidance and energy that supplicate insight, if you want to “see” the way out you need to purify mind first. If you think sitting certain way or moving certain why is the “hack” – that’s a big misunderstanding I would say. That’s to say you can not study Dhamma on your own or even with Lal texts as they are just text-books for teacher to explain you. You need to be in presence or hear audio or have special texts that holds the energy of Buddha Guna that purifies mind, certain suttas holds this energy (that’s why people chant it and enter jhanas). Dhamma is simple but not necessary easy if you are not gifted with a lot of white kamma and merit.
About Sotapanna leaving “the Path” – well I think that may happen, most people after attaining Sotapanna would be probably Neyya type, Neyya from what I understand needs further explanation, either from properly understanding sutta or having the right sutta that push person higher or higher person that can point out to the limits of his attainments like Anagami probably could help Sotapanna better than other Sotapanna. I read somewhere in the suttas that person/monk who wasn’t even Sotapanna helped to move Sotapannas higher by chanting suttas – so suttas holds certain purification effect if you have base you may figure it out but those Sotapannas may be actually higher type of people (above Neyya) this is gray area for me, so I can not really speak deeper about this but on the outside it maybe seemed simple as above but if you try to analyze it deeper it will get complicated and without Buddha insight is hard to judge those things right, and it may turn into guessing game.