I'll be in the same situation as you when I'm in grad school next year, so I'm interested to see what others say. However, I have a bit of experience with this in the sense that, up until about 2019 I have always worked 3-4 jobs to make ends meet. I would work my "full-time" job which would be about 4-10 hours a day depending (it was an awful environment and unknown schedule, 10/10 do not recommend) then once I left there some days I would go home to do my virtual assistant work, or go to the office of my therapist friend where I would do her bookeeping/admin work, or go to the university to proctor (before or after work) for about 4-8 hours depending. I worked all of these jobs 6-7 days a week, I had absolutely no time for myself.
It was a necessity at the time to work this much, but I definitely started to take notice of burn-out and it's effects on me and slowly started to schedule more time for myself, without impacting my work commitments (as I couldn't afford to adjust my schedules). I found it really helpful to do block scheduling,
here's a quick breakdown.
That allowed me to prioritize my work schedule while also physically setting aside time for my self-care and personal needs.
I kind of gave up block scheduling when I got a full-time job 3 years ago that had a set schedule (and better pay) and went down to only doing my freelance content writing and virtual assisting in a more relaxed way - taking on projects when I know i have the time, or small projects that are easy to complete in an hour or two. That worked for me for a while, but I've found myself falling back into the habit of prioritizing work, other people's needs, etc over my own again and feeling some burnout from working in healthcare during the pandemic so I'm considering starting to use this technique again. It will also get me back into the rhythm of things for when I start school in January and need to prioritize my school commitments on top of my work ones.