My comic was a lot easier to maintain when I worked in trades, as my schedule shifted between full-time and part-time. The financial instability was a bit stressful and eventually forced me to look for a new job.
Unfortunately, I didn't have just A and B to choose between, because about 8 months into my fulltime job, I got really sick and for months after, my life has been limited to going to work, getting the absolute bare minimum chores and tasks done, and sleeping. I haven't drawn a comic in months, and it's so hard to have to choose, but until I have financial stability or my comics garner enough attention, I can't choose comics over my day job.
I will say this though: I have a friend who works in the movies and games industries and just saves up money to support herself between contracts and uses that time to work on her comics. It seems to work out really well for her, so there is a bit of a have-your-cake-and-eat-it-too that exists for each person if they're willing to prioritize and dedicate time.