No, living under survival pressure is good for mental health. It's what we're evolved to do. Why does it feel good to crack a tough bug, or finish a project, or win a game? It's the same achievement reward a hunter feels bagging a deer.
With survival pressure, most people die. See that Alone show, most people get at best 2 months done and then thats even before the harsh of the winter really sets in. Just hard to establish enough systems to bring in your daily caloric needs without anyone to help you. You really need the tribe to make survival actually manageable. And in tribal societies all over the world we see how delegating the needs of survival has lead to a lot of other benefits, such as time to iterate on cultural ideas.
I know lots of people struggling to get by and I can assure you their situation doesn't improve their mental health.
Some pressure is good but there's a difference between constant pressure and regular sessions of pressure similar to hunting. I don't think we necessarily evolved to be under constant pressure, I'm not saying it's impossible but humans wouldn't thrive under constant pressure, we'd never have had the time to evolve language or the intelect under constant pressure.