Don't engage in a full-split for the week. Muscle protein synthesis happens for 24-48 hours so optimizing that while you are studying is key. Instead focus on completing full-body workouts three times a week with a day of rest in between. Mondays, Wednesdays, Fridays are for your full body training while Sundays could be for HIIT training (max 30 minutes).
Focus on compound movements primarily and complete them in two sets instead of three with about 2 minutes in between each set for rest. Workouts include Bench, Rows, Presses, Pulldowns, Deadlift, Squat, and Cable Crunches. Those seven workouts alone will work the whole body, build neuromuscular connections between various muscle groups, as well as provide the maximum tension across various muscle fibers.
Resting between sets optimizes overall volume and has been shown to increase muscle mass faster than if you shortened your rest to under a minute. What I like to do during this time is pull out my phone and use an app called Quizlet to get familiar with formulas and general concepts while I'm resting. As I set a timer during the workout, I just keep track of my rest periods to a tee. By shortening your sets, you can focus on adding weight and reps to regulate your overall work capacity. By increasing those progressively, you will see gains while optimizing your time in the gym.
Diet is also crucial. Without proper attention to that, your time in the gym will mean nothing. I'd recommend preparing food in a combination of a slow-cooker, toaster oven, boiling, and steaming to get your foods made fast and pack them away so you are consuming the appropriate macronutrients and calories to promote muscle gain. I'm a vegan, so personally I do a lot of steaming and just bake any proteins I need so I can gobble it down. I also take protein shakes and fruit for preworkout. Stick to an app like My Fitness Pal to track your macros and you should be golden.
As for optimal diet and nutrition while in school, I recommend a moderate caloric deficit of 500 calories from maintenance with about 1.3 grams of protein consumed per pound of lean body mass. Since engineering students spend a lot of time sitting down and studying, it's best to try and build muscle while keeping off excess fat. The best way to avoid gaining fat is the caloric deficit and the best way to build muscle is to increase protein intake. Just log your foods as you eat them, and you're good.
Time is crucial with any system. I run my own online UI/UX business, ecommerce on Amazon, while working as a grad TA and full time student at Stanford. Oh and, using the methods I've mentioned, I've also competed in natural bodybuilding competitions across California. Though in all fairness, I haven't really placed very high. Building muscle is a journey friend, keep improving every day!
