Say you make 50k salary, how much more would you need to be making from side gig to quit the 9-5? Salary is a guarantee, how much extra do you account for the risk of giving up the guarantee? 60k? 70?
Of course this doesn’t account for self employment tax, health insurance, retirement benefits included.
I’d do both. I wouldn’t quit until I was sure the income was steady. That might be after a year or two.