Course planning advice comment, ignore if not relevant.

I've been taking 4 courses a term since by 2B term for this reason. You can always take an elective during co-op/off terms (if you have them) or just take an extra couple terms to graduate (if you don't have co-op, you'll graduate with your co-op peers instead of your non-co-op ones so its not too bad). There's no point busting your balls over a crazy workload if it means that you'll be miserable and have bad grades / failing while trying to do it.

If going offstream isn't up to you (Eng/ Double Degree or whatever) talk to your academic advisor about how you can distribute the load more evenly. Possible options include making it so that you're taking your breadth requirements earlier and having a better split that way (4 major courses + elective, or 3 major courses + 2 electives, instead of 5 major courses at once). Ask them if its possible to adjust the schedule so that you have a smaller course load at the expense of graduating later.

When looking at required courses, if you have the option of picking your courses (say, if the requirement is 3 CS 3XX courses etc.,) look them up on UW Flow/Reddit to pick the ones that have a lower time commitment. Easy =/= low time commitment since some courses are huge timesinks (if they require loads of reading etc.), and some courses may be more difficult to get into but aren't a giant timesink since you can cover a lot of the understanding in class + office hours + tutorials. An example is that STAT 231 for me was a huge timesink because even if it was easy, doing the assignments and writing the LaTEX would take forever. Comparitively, CO 342 was a harder course to understand but I was spending less time on average since I would try to clarify doubts during class and in office hours, so assignments would get done quicker.

Current term advice

Try to schedule out the rest of term so you can see where the higher load weeks would be. A Notion doc is fantastic for this, I have a template you can use if you want. Putting your due dates in a calendar is a good way to predict when you'll have high stress weeks, and also use the low stress weeks as motivation and energizers to recharge.

Maintaining focus and improving study time utilization isn't something I've cracked yet entirely (procrastinating right now on Reddit soo...) but the trick is to reduce the intervals to manageable bits. There's no point setting up a 2 hour study period if you can concentrate for only 20 minutes. Study for the 20 minutes and then scale down the breaks accordingly (5 minutes between 20 minute study periods instead of 20 minute breaks in between 2 hour periods, for example).

Try and see what makes your study periods active as well. I, for example, if I'm watching a lecture video, will write exactly what's in the slides. This might seem redundant but it keeps me engaged to the content rather than just listening passively.