If “it doesn’t last more than a day or two”, then I feel like what you’re describing isn’t the same level of burnout being discussed in the article; you’re noticing it and dealing with it before it spirals out of control. Which is a good thing! (and a life skill I wish I had learned much earlier in my life!)
But I’ve gone into that burnout spiral twice in my life; the most recent time (the worse one) was over a decade ago. That burnout was the result of nine continuous months spent in intense crunch on a project I hated but couldn’t leave, along with some other ongoing stressors.
After shipping that project, it took me more than two months of time completely off work before I even started to feel like I was a human again. And then two more months before I started to feel like I wanted to start doing work again. I was absurdly fortunate that I had enough long service leave saved up to afford to take the time I needed. (or alternately, the fact that I had all of that available time off which I hadn’t taken maybe wasn’t the best thing for my chances at avoiding burning out in the first place. That’s a totally valid alternate take on the situation!)
I do agree with your comment that burnout isn’t a “final state”; it’s something that most folks will recover from, given enough time, and it typically gets worse the longer you don’t deal with whatever’s triggering it.
For me, when I was in the middle of the burnout it didn’t feel like a thing I would ever recover from; I just wanted to be left alone in an empty room all day every day and never have to talk to anyone or think about anything ever again. And eventually my brain came back to me and I came out of the burnout. It took a long time, though.