I've done the sabbatical thing and I ended up keeping my job. The sabbatical was a life changer and it led me to Rich dad poor dad, then real estate, then here to MMM and now I'm about to FIRE in 4 months. The sabbatical was 6 years ago. Back then I had no direction and no hope, was totally burned out by my cubicle engineering job, miserable,depressed, and wanted to quit. When you feel like that and you're always busy you have no creative energy. The cubicle leeches your life and leaves you with nothing but a shell of a person to go home, eat, and then drudge the commute back to work the next day. It's terrible and I feel your pain. So I kept my job because I had lots of vacation saved up, took off over the thanksgiving and Christmas holidays allowing some extra free days, and using some unpaid leave. They approved it and I was out 14.5 weeks. Did you know you accrue vacation while on vacation? Haha. The magic time occurs after 3 or 4 weeks when you finally start forgetting about work and your creative mind comes back. It was then I found my way out and finally had hope.
My wife actually quit her job for this time too and we took a 3 month trip, but her job wanted her back. She got a raise and negotiated less in-office hours! The power of quitting right there.
So, yes, try the sabbatical first (try negotiating using your vacation and any other leave then tacking on unpaid) and if you still can't go back then quit. At least you'll have that safety net and some time to make an informed decision. Right now you're emotional and just want to GTFO. Understandable.