Do schedules and deadlines cuck my natural inclination to feel free or is giving my free time no structure an invitation to be cucked and maniplulated by the modern world?
Not structuring your time is the biggest cuckoldry there is senpai. Literally getting jewed out of your life.
You can do it without losing all your fun - just say, "from 6 to 9 I'm gonna do jack shit, drink, and/or watch anime" or whatever, along with scheduling your work. If anything, you'll end up with more time to relax, and you won't spend that time worrying over not getting things done, because you know you've already set aside time for that.