Read the contract. Does it say "terminate employment" or "quits". For most sign on bonuses you only lose it if you don't fulfill your end of the contract. If they fire you, you don't owe them anything. Tell HR you're feeling burnt out and need some time for family... In writing. Then be less of a perfect employee. If you're doing a PhD level job, mental health is a major part of productivity. You and the company have a vested interest in achieving an acceptable work / life balance. They obviously want you to stay. Be honest with yourself and find out what you can do to make it work.

If you live in a country that has free higher education, it is likely your living under a huge tax burden filled with bureaucracy and waste. Tax accounting will be the last to automate because AI drives efficient spending. That money isn't disappearing, its being delivered into the pockets of political figures and government mangers.

If we could do this on a global scale it might make sense. It sounds like what he actually wants to do is export the jobs we haven't already given away to China.... Too Germany.

The private sector already works like this. I work with a guy we call "bad decisions". He's paying child support to four different baby mommas. Of course they all got their side hustles, but that child support check is what pays for the basic necessities.