TL;DR - 20 minutes of self-testing beats a 2-hour lecture. Testing is friction, and friction is learning.
Going to lectures is mostly a waste of time. Unless you're sharp as hell and deeply motivated that day, you will not pay attention.
I tried going to lectures as a freshman - mathematics and the rest - and found out I'm not the type who can absorb theory by sitting and listening. Then I started digging into how learning actually works, and it turns out most people are like this. Almost nobody remembers a lecture.
That's where I discovered testing. Testing yourself is probably the highest-leverage thing you can do for your learning. It's friction: you have to think, you have to produce the answer, you can't fake it. Instead of two hours in a lecture hall, test yourself for 20 minutes - same coverage, deeper understanding.
Active learning or passive learning. If you want to be an exceptional student with a great career start, you know which one to pick.