I work in this area of research. The issue is the headline findings from all of these studies will get reported and people will comment on how it’s obvious or offer their own explanation. The truth is that it’s a very technical / stats heavy field with a lot of the results depending on the assumptions you make and how you treat the data. The results then have to be qualified with ‘there is a positive relationship, given x y and z’. But of course that’s usually too complicated to report so all of those details get omitted, and all we are left with is a simple statement followed by hot takes from the general public.
It’s tricky to know where to start but I’d recommend searching for papers by Andrew Clark on Google Scholar. Then you can read other referenced studies if interested etc.
What you are looking for here are studies looking at the relationship between income and subjective well-being (sometimes shortened to SWB). This is the general term for self reported measures of well-being, though of course this can be broken down further into more detailed factors such as affective (how are you right now) and cognitive (how satisfied you are with your life overall).
