Burnout is a self-help book, so no surprises here: there’s a rather chummy writing style with simplified, bitesize “science” (some of it feeling more dubious than other bits), and there’s a fair bit of colloquial, “relatable” stuff like saying “(ugh)” every time they write the word “patriarchy”. The book is focused on women, or at least people who were assigned female at birth, and throughout it assumes that it’s speaking to women and that women are the only people who would benefit from the advice contained therein. I don’t think that’s true, though I think some aspects of burnout that they discuss tend to impact women more.
There are some interesting ideas and bits of advice in here, and the ways in which it emphasises exercise — or doing some kind of analogue for exercise, like lying down and tensing each muscle sequentially — are fairly doable for anybody, without an undue emphasis on fitness/weight. There’s a section about body positivity which is probably useful for some folks, and which emphasises the ways weight loss is a con.
Overall, I’m probably never going to be a huge fan of self-help books, but this one has useful information and is probably accessible to just about anyone who can put up with the sex/gender assumptions being made. It is probably not going to fix your brain; it certainly didn’t fix mine… but it can offer a useful perspective.