Can idiopathic hypersomnia diagnosis by sleep study respond to anything besides stimulants & sleep hygiene? Anything off label? Foods? Research being done?

Hyersomnia. In case of hypersomnia, the overnight sleep study is not enough alone, another study called mean sleep latency testing is needed to evaluate the severity of hypersomnia and to rule out narcolepsy. If you were told that you have idiopathic hypersomnia, i presumed that you had already mslt and narcolepsy was ruled out, anyhow stimulants, sleep hygiene modulation and regular exercise are the best.
Narcolepsy? You may have narcolepsy. Gamma-hydroxy butyrate has been helpful in that condition, by improving the quality of night time sleep.