The reason your most "profitable" client is actually bankrupting you is simple:
You priced the work based on creation time, not management chaos.
Add a 30% buffer for emotional and operational support before you send your next proposal. Charge for the actual human you have to deal with.
https://jawestenberg.substack.com/p/price-your-work-for-the-shit-youll
@Daojoan I did this, after about a year of talking myself into it. It felt really scary at the time, but my hope was that it would either encourage him to fire me, or we’d continue working together at a rate that made me feel a lot less resentful. It turned out great! (If I have one regret, I should have gone for 35%.)