I’ve lived in very expensive cities (Boston, Los Angeles) and now live in a moderately priced one (Cincinnati) and most things cost about the same except real estate. Gas (which I don’t use as I have an EV) is a bit more in California due to taxes but food, clothing, services, gadgets, utilities, etc are almost the same.
If I were a 20-something today I’d stay away from high cost cities. Real estate eats everything. I might consider living in such places for a little while to build network but would bug out after maybe two years. For example I’d say if you live in SF/SV and are approaching 30 and making under 300k you should leave.