if self teaching you need a book that holds your hand and doesnt try to put you through the usual trials of "lets see if you can figure this out yourself.. oh you cant? maybe repeat the subject next term", or major proofs left as exercises for the reader. get a friendly hand-holdy book. im reading linear algebra, theory, intuition, code by mike cohen atm (up to ch4) and so far between that and a chatbot for clarification/links, im re-learning the L.A. i should have learn't at uni but for whatever reason just did not understand back then. those courses move fast and if you get stuck somewhere its game over. i think L.A. is way harder than calculus as a beginner, but once things start to click and fall into place it starts to feel easier.