I’ve heard that Shaar Hayirah in Reshit Chochma is supposed to be very powerful, however a lot of rabbonim won’t let their talmidim learn it as apparently it’s so scary it gets people depressed to the point some of them go off the derech chas v’shalom. I’ve learned with a big talmid chacham who whenever I’ve asked him to teach it to me he casually changes the subject, so not sure if it’s so shayach.
Davar acher – I personally really like charifkeit, however even so often I find that something really deep and inspirational can motivate or change me much more than many instances of being scared. Try learning some chassidus and see if you can catch what I mean.