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.
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.