Do you have any advice on how to plan a successful sabbatical leave?
Eventually I settled on a flexible routine of going for long walks, teaching my kids, cooking, taking care of the house, reading, working out, etc. Now I feel content and don't miss being "productive".
Maybe that is what you need if you are burnt out.
First few weeks, I was still a wreck from work, and had a lot of lounging in bed. That's ok. That's part of decompressing... I wouldn't characterize it as "be[ing] a slob" just because you're not feeling productive. The whole point of needing a sabbatical is because you've (presumably) forced yourself to be too productive for too long in the face of too much adversity. For me, success in those first few weeks was just getting out of bed and showering every day, even if that's at 5pm.
Then, after getting my second vaccine shot, I took off on a multi-month road trip, checking out national parks I hadn't been to before. By then, I was actually feeling more alive, and spending time outdoors had me realizing that this was what I was actually working for. I made plans 2-3 days in advance, so I was flexible enough to stay in some places a bit longer if I wanted to. And, other than that, didn't do much.
Eventually, I worked my way back to my hometown, and booked an airbnb for a few months, and spent more time with friends. By this point I had a bit better idea of what I wanted to be doing, knew that my current job wasn't going to give me what I needed, so applied for different work. Got offers, accepted a job, quit, and then eventually had to race back to the Bay Area to start my new job.
The funny thing about the whole experience was I wish I had committed to an entire year off. I felt like I was just starting to heal and get my zest back, before being thrown into the stress of starting a new job. But, the overarching learning was that I need to make larger shifts in my life, and the new job is just the first of a number of changes I need to figure out.
I think a sabbatical to combat burnout (as opposed to an academic sabbatical, where you're off learning something new) really shouldn't be planned. Talk to your physician about how you're feeling and see if they have any recommendations. Talk to HR (after you talk to your doc) about what options might be available. Commit to multiple months off. Don't be hard on yourself about having set goals. It'll likely take 2-3 weeks to relax enough to even have any insights into what your next steps could be. Then go with what you find interesting or intriguing. At some point you'll likely naturally start picking up on things that you like or don't like, and directions to take your life. And then that can lead into figuring out your next steps.
I know a dozen or so people who have done this in the past two years. Some have returned to their jobs, some have left for jobs in new areas, some have switched to consulting, some have started companies, and some have decided to pursue more education. If you're lucky enough to have the ability to take time for yourself, then just do it. Not having a plan is terrifying, but it's in that terror that you can really learn a lot about your passions.