@izzythepush,
When my significant other, Marvelous Maxine, wanted some soothing bath oils I recall researching essential oils. It recommending diluting the oils as they can be powerful (meaning skin irritation).
I think I was looking up lavender oils but found others recommended diluting them too. One second while I pull it up:
There is no need to dilute lavender essential oil with other liquids but you may use water or your favorite oil if that’s your choice (expensive).
OTOH, Tea tree oil can be a little irritating on the scalp but is excellent at cleaning the scalp and is considered helpful for dandruff prevention.