Those courses you mention are a part of a much larger "personal development" market that really boomed in the 90s, and keeps going on ever since.
There's a book called "Letting go: a pathway of surrender" and the part that really jumped at me is that the author lists dozens of different flavors of that "personal development" offerings:
“Well,” you say, “there have to be some experts who have the answers.” When upset, you go to a doctor or psychiatrist, an analyst, a social worker, or an astrologer. You take up religion, get philosophy, take the Erhard Seminars Training (est), tap yourself with EFT. You get your chakras balanced, try some reflexology, go for ear acupuncture, do iridology, get healed with lights and crystals.
You meditate, chant a mantra, drink green tea, try the Pentecostals, breathe in fire, andspeak in tongues. You get centered, learn NLP, try actualizations, work on visualizations,study psychology, join a Jungian group. You get Rolfed, try psychedelics, get a psychicreading, jog, jazzercise, have colonics, get into nutrition and aerobics, hang upside down, wearpsychic jewelry. Get more insight, bio-feedback, Gestalt therapy.
You see your homeopath, chiropractor, naturopath. You try kinesiology, discover yourEnneagram type, get your meridians balanced, join a consciousness-raising group, take tranquilizers. You get some hormone shots, try cell salts, have yourminerals balanced, pray, implore, and beseech. You learn astral projection. Become a vegetarian. Eat only cabbage. Try macrobiotics, go organic, eat no GMO. Meet up withNative American medicine men, do a sweat lodge. Try Chinese herbs, moxicombustion,shiatsu, acupressure, feng shui. You go to India. Find a new guru. Take off your clothes. Swiin the Ganges. Stare at the sun. Shave your head. Eat with your fingers, get really messy,shower in cold water ........
The point is that there are thousands of people out there who would be happy to take your money to tell you about your problems and subconscious. :)
From what I understand, EEG is very difficult to analyze, and does not have the accuracy that you are seeking.
From my personal experiments, observing the intensity and content of dreams may offer some insight into one's subconscious, however it is extremely subjective.