Cs, you don’t need chasidus to answer that question. Actually, it’s essential to have the basic yiddishkeit hashkafic answers to such questions first before delving into kabalistic concepts. Jumping ahead leads to lots of confusion. Before touching tanya and other chasidishe seforim, i learned ramchal, and some pieces from rishonim who deal with hashkofa issues extensively.
It would help you to learn the ramchals derech Hashem and mesilas yeshorim in the very least. Seforim like emunos vedeos or shaar hayichud in chovos halevavos might give you questions you didn’t already have in emunah, so maybe don’t go that route.
Anyways, to answer your question. Again, you can ask better – we see in chumash that Hashem gets “angry,” which also implies that there’s a timeline, a change. Hashem also says that He “regretted” making people by the mabul. What does that mean? It means not that Hashem changed, but the creations changed. The creations were no longer within the parameters of Hashem’s intention when they were created. The creations’ actions arouse heavenly mercy or strict justice, but that’s from the outside in: Hashem never changes. Same thing with nachas ruach – there are certain actions which are in sync with Hashem’s will, and cause the creation(s) to be in line with the purpose of creation, which was to bestow upon man Hashem’s pleasure(see mesilas yeshorim perek 1 for elaboration). Hashem, being the ultimate Giver (maitiv) created the world not for Himself, as He lacks nothing, but rather to give to others a perfection that he Himself has, on their finite level.
That’s ultimately what dirah batachtonim means on a basic level; having that dirah is what’s best for us, the created. Any interpretation, kabalistic or otherwise, which implies that Hashem os missing something, has violated the 13 ikkarei emunah.