>Is some big boring company making billions with it? If so (quantum physics) then it’s legit. If not (healing crystals, orgone energy, essential oils...) it probably doesn’t work.

That's no guarantee; in 2020 the US essential oils industry was worth $18.62 billion: https://www.grandviewresearch.com/industry-analysis/essentia... . Which is bigger than the US music recording industry (https://www.musicbusinessworldwide.com/the-us-recorded-music...).