I'm 58 and recently diagnosed with AuDHD. I've had several burnouts in my life, beginning in college. As I get older, it seems they are more frequent although now that I know it's not depression, I can scale back. I, too, am "academically intelligent" with 2 master's degrees, but I find the workplace quite difficult. I have great trouble with ambiguity and also perceiving authority. Both have caused many problems. At this point, I cannot work outside the home because to do so would be to risk more burnout. I write, but it's tough to make much $ that way. I've been socially confused my whole life but didn't know how to identify it correctly. You might find a couple of my articles about my experience useful:

https://medium.com/invisible-illness/pretending-to-be-neurotypical-23d50e8ca89c

https://medium.com/crows-feet/late-life-autism-diagnosis-relief-and-anger-1fdb02ed8daa