I actually wonder if you're an engineer at Meta because this isn't my experience at all. My whole team (in London) is working hard doing useful engineering work. The evaluation process is such that employees are pressured to deliver. I haven't seen anyone "relaxing".
To me, the problem with Meta is the constant focus on impact. There's little incentive to write robust software. Many tools are half-finished, fragile, poorly documented.
I did the other way around. Went from teaching (university level) to FAANG. I could discuss for hours about the pros and cons of each job, but the bottom line is that I can't afford not earning that money. I'll save every single dollar I can from my SWE job and think about something else when I'm laid off, but I'm not leaving on my own.