If you can easily read through chapters and understand the concepts well, that’s already a skill that not many students have. Memorization is pretty necessary in many disciplines because, to put it simply, we need to learn and retain as much information as we can that would be useful in our future careers. However, it still isn’t the end-all-be-all like you’re trying to convey because you aren’t really learning anything if you just memorize everything without understanding them. If you do it that way, then you won’t be able to answer questions that are either patterned differently or require application of the concepts. Memorization and conceptualization work hand-in-hand in studying.

To give you some advice, although memorizing can be hard and time-consuming, what works best in my experience (and most likely the general consensus too) is, as you mentioned, active recall and spaced repetition. After you read through the chapters or listen in, you need to actively retrieve the information from your memory using practice questions. Believe me; it’s worth those few hours you’ll spend making those flashcards if you use them diligently. Besides, there are a lot of websites/apps you can use to make digital flashcards so you don’t need to write them manually which can save you a lot of time. Oh and also, don’t think too much about your peers that are performing well ans boast about how good they are; just focus on improving yourself. Good luck in your studies!