The phrase "chemical imbalance" can't die soon enough. I've met some very smart people who were misled into thinking there's much more scientific evidence than exists that there's some innate brain chemistry that's linked to mental illness. In general, people overestimate how much of psychiatry is first-principles instead of black box statistical conjecture. The first huge hint that there's no simplistic chemical imbalance explanation is they don't measure any brain chemicals when they do psychiatric diagnosis.
Furthermore, when people discuss "chemical imbalance" they're almost always talking about something innate and unchanging e.g. I'm depressed because of a chemical imbalance, not my lifestyle. When there's actually a ton of evidence that to the extent there's chemistry in your brain, your lifestyle and things like your food diet and information diet play a massive role.
I will recommend this guy in way too many comments here but if you haven't heard of Andrew Huberman, please listen to his podcast, it's been life-changing. He gives tons of lifestyle tips and backs up all his arguments with his decades of experience in neuroscience.