Apart from housing the costs aren’t that much more. You pay the same to travel. You pay the same to buy stuff online. Food is maybe slightly more but it’s not that significant.
Once you get past being able to afford housing it’s insanely lucrative. It’s harder for entry level people of course.
I have had that discussion multiple times with people. They all seem to think you absolutely need to live in a 5 bedroom 5m$ house in Palo Alto (because how else are you going to live?).
But if you rent a normal 2BR for 4000$ in the Bay area, and could potentially rent the same for 1500$ in a LCOL, that is a minimal saving compared to your income. Everything else stays mostly the same. An on top of that most companies will give you a paycut.
But for some reason people think you are going to be a king just by moving to LCOL. I think it is the opposite
Now, if you get bamboozled into buying a 5000 sqft house like the average american does, then yes, big savings in a LCOL.