I think it’s true that the Torah has everything in it already.
Parshas Ha’Man is a segulah that if you say it everyday you will never be missing food from your table
Parshas Ha’Yirah is a suglah for yiras shamayim
Parshas Ha’Teshuvah is a segulah for teshuvah
Learning Chumash Rashi is supposed to be a segulah for Emunah
I heard a story of a ba’al eitzah who would always say all taryag mitzvos before he would eat. Someone once askedim for a segulah for something and he said that he doesn’t know much about segulos but saying all taryag mitzvos before you eat soup is a segulah to cool off a hot soup
But still the Rishonim and Achronim didn’t put out sifrei mussar and machshavah for nothing. We are supposed to learn these things in addition to learning Torah. So that being the case if someone is looking to work on a particular area such as yiras shamayim or is especially worried of his din WellInformedYid provided us with options that one can learn during ‘mussar seder’