I would argue that the relationship isnβt at all linear. Just take a look at the dunning-kruger curve or the hype cycle curve to get an idea how wildly these things can fluctuate.
You have it. You could also say that the graph is linear, but with different zero values ("problems" has a bottom of N > 0), but if we're judging from IRL, it's more like a parabola.
As your debt grows, your problems increase very gradually, maybe even asymptotically. As your wealth grows, your problems increase roughly linearly, but the slope is steeper than with debt. In between the two, thereβs the sweet spot with the least amount of problems.
According to some studies, happiness increases based on income. However, you will run into diminishing returns pretty quickly. In higher income levels happiness also becomes more complicated, so itβs pretty hard to tell if money is really helping at that point at all.
The sweet spot could be somewhere between 50 k$ and 100 k$ per year.