Reading the declarations of this Council quieted many of the concerns I had about the Faith and helped unify my understanding of many different concepts within the Church; especially those that relate to Grace. I feel like this should be required reading for any catechesis class. It's short too:)

Not to be snotty or anything, but I was always want to ask, more often than what?

Anyway, basic classes in catechesis like RICA, CCD etc. don't tend to cover much in the way of heavy theology, largely on the basis of the assumption that most people won't understand it anyway.

One resource that I think is overlooked all too often these days is the Roman Catechism, also known as the Catechism of the Council of Trent, first published in 1566. For a catechism, it is surprisingly dense, with a lot of information, some of it very deep. You can get it really cheap (something like $1.99) for the Kindle, if you want to read it, don't try to read it like a novel, take one chapter a day and read it, it will take you months to get through the entire thing (I've been reading it on and off since 2015, and I'm not even halfway done with it) but you will be surprised by how much you can learn. By comparison, the universal catechism of 1992 is a pamphlet.

You may be atypical in your desire to understand in depth. I think this would zoom right over the heads of many people.