But also understand that you're probably not going to make the best decisions about this from the perspective of extreme burnout.
First step might be to talk to your boss about your workload and see if there are some changes that can be made to make you happy again. If that doesn't pan out, maybe think about finding a new job. Even if you choose not to, just going through the process of seeing what's out there will give you some valuable perspective.
I don't have much idea as to how difficult it'd be to find another job in your 40s/50s if you take an extended break from work for a while, but my intuition is that it'd be harder than simply switching jobs now. An alternative might be to find a new job now, but negotiate a start date that is a month or two out from your planned last day at your current job. This won't work at some employers, but many will be fine with it.
On the other hand, consider that $2.8M at $80k/yr is 35 years of expenses. Your expenses will almost certainly grow over time, but even if they triple, that's still over 10 years of runway. If you wanted to take a year off, but then had trouble finding a job right away, you'd have no problem (financially) taking 6 months (or 12 or more) finding your next job. Hell, you could train for an entirely new field and work your way up from an entry level position to something mid-range in that time.