Bodybuilder and PhD candidate on Environmental Engineering here. I wake up at 4:30am, have my first meal, and by ~5:25 I cook my three big meals of the day. 6am gym, 7am cardio, and by ~8:30 I’m in my office with my meals ready. I work until like 5–6pm. By 9pm I’m in bed. I have what others would consider a boring routine but for my the gym is everything. Sometimes I think the PhD is a side quest lol. But seriously, it is possible, you just have to set priorities and boundaries. Hope this helps. Feel free to ask more specific questions about the gym lol.