This isn't quite the answer you were looking for, but I absolutely have taken sabbaticals in my career when I was feeling burned out. It absolutely helped and r

This isn't quite the answer you were looking for, but I absolutely have taken sabbaticals in my career when I was feeling burned out. It absolutely helped and re-energized me, and I usually needed 3-6 months off. I'm doing it again at the end of this year, FWIW. But I did not negotiate it with my employer, I just quit. It will be hard to truly disconnect if you know someone out there has a timeline when they expect you back. Instead, I'd leave things open-ended. If you feel better in the future and want to go back, and they want you back, great. Or maybe you'll find a new direction and not ever want to call them back. That is great, too. Leave yourself open to whatever comes your way.