I wish you the best of luck on your future endeavor. I admit I never quite managed to just pick up a textbook to read through ahead of time, though it would have (perhaps) helped.

I would give a few pieces of advise to my younger self, and I think they should still be valid for others:

First: it is very important to sleep, for a bunch of learning-related reasons. But, perhaps more measurable: if you feel the need to pull an all-nighter, it is very likely you are falling behind and trying to crunch your way through. I'm not saying don't do it, because if you are there, you are there, but maybe take the opportunity once it is all said and done to see if you can avoid it in the future, yeah? Sleeping enough is cool, and helps you learn better.

Second: understanding the fundamentals really helps you understand everything else. I struggled with some of the mathematics classes in my course exactly because I did not have a solid grasp of the fundamentals.

Third: you're going to be in class anyway, so pay attention (not that I didn't) and then, afterwards, review the class. Probably by writing a summary/notes about it. The point isn't to produce something that I can then look up, but to see what I retained and what I didn't, and thus I should review.

Fourth: put it into practice. Try to teach others (even if it is just a video you're never going to upload to youtube), or work through a project that exercises it. Theory is great. Toy exercises are great too. The best thing my university did for us was to get us 2 weeks worth of project at the end of each semester.

Fifth: the better you are at language, the better you will be at everything. Why? Simple: your classes will use language to transmit the knowledge to you, whether spoken or written. You will use language to transmit your answers to whoever is grading you. You can have the most amazing teacher and the most amazing learning materials, know all the right tools and techniques... but if you cannot really parse and understand what you are hearing/reading, then you won't learn. Likewise, you may know the material perfectly, but if you cannot articulate your answer? Not only will you not get good grades (which sucks), you will later on struggle to work with others as they, too, need to understand what is going on.

There are plenty of tools to help with all of the above. Index cards are great, whether physical or digital. But I would try to avoid falling into the pitfall that highlighting/underlining or writing notes is learning. They can definitely be tools for learning, but I have seen people who were prolific highlighters and note takers who did not have such a great domain over what they were supposedly learning.

My recommendation is that you team up with a group of other engineering students from your classes when they start and meet with them everyday that you can; even if you're not working on the same assignments. People carry different talents: some pick up information quickly, some can find links others missed, some have a knack for explaining things in an understandable way and some just bring positivity and relief to the group in stressful situations. Everyone can help each other and when you find that group and stick with them everyone succeeds. I know people have social anxiety sometimes but when it comes to your career and life it is critical that you expose yourself to the uncomfortable. If you love being in groups, invite people who might seem shy to join your group. Almost everyone has something to offer so succeed together and make lifelong friends at the same time.

for me 2 things that helped a lot were:

1. hand-writing my study & lecture notes - i got made fun of for this but writing things out with pen & paper helps cement them in my brain and retain them better. maybe it won't work the same way for everyone but i found it way better than typing things into a file that i will probably forget exists. i also find it easier to review the material this way because i can organise it my own way and recall where things are in my notes.
2. not doing too much - sounds a bit counterintuitive! but making sure i wasn't cramming, wasn't spending every free hour wallowing in information, letting my brain have healthy breaks and getting somewhat sensible sleep. it can be hard because you may feel like "ohnooo i should be studying" but for me, my brain needs that time to process what i have been putting into it.

ymmv but these things helped me a lot through both a BSc and MSc, and i even practice these same things now with learning how to draw!

If studying is something you've struggled with for 6 years (I'm assuming trying several ways to force yourself over those years without success) then it might behoove you to get screened for ADHD or other learning disabilities. I dropped out of my engineering program and only years later understood why I couldn't deal with it.

Can you be more specific about what you mean by struggle?

Caveat: I got my last degree a couple of years before AI took off. I would consider any advice through whether the person offering has a lens of pre or post AI.

The advice I'm confident would apply to both is to take advantage of study resources. Meaning open office hours? Go to them. Professor's aide is offering extra lecture sessions? Go to them. Dormmates forming a casual study group? Join. Discussion forces depth of thinking that passive consumption doesn't.

I mean its pointless to know and not do it. I could not even keep up what is the best way but I will go through it. Do the readings and even get a jump on them. Hand written notes in class and tape the lecture in case you need to check something. Go through notes and readings and rewrite the notes better. Every time you get close to a test take all notes and rewrite them again and again. condensing down to most important points and concepts. Get it down to like a page or two as you get to the night before the test and know that inside and out.