When I was freelancing and still studying 60 hrs a week.
~20 hrs. bread-and-butter job
~20 hrs. for University
~20 hrs. writing a full-stack application for a startup

I did that for about 3 months, afterwards I luckily had no classes left.
Only, the thesis is still open. But on the other hand, the freelance work for the startup was a pretty good reference for scoring an actual, well-paid position which made me leave my old job as well as freelancing.

Now I work roughly 40 hours a week with nearly as much freedom as a freelancer but less paperwork.