This might not be well-founded at all, and it might well (and could even likely) be the case that higher levels of happiness lead to clearer thinking.
I suppose I was thinking about a bit of a dichotonomy between analytical, focussed attention and expansive awareness (while I appreciate that this is an oversimplication, something like the distinction between 'left-brain thinking' and 'right-brain thinking'). My understanding is that''left-brain thinking' can contribute to anxiety and cause one to be overly critical of oneself, but can also facilitate critical thinking regarding whether e.g. a cause area which seems noble is relatively more important. 'Right-brain thinking' might facilitate greater creativity and imagination (for which this course would, I imagine, be helpful), but may lead one to be less analytically rigorous.
I definitely agree that it's important to consider facets of a career other than impact, but personally I wouldn't want to use the weighted sum approach. I'd prefer to mostly think more about thresholds and aim to 'satisfice' in most areas other than impact.
It's very important to have boundaries and avoid burnout but if you have a reasonable sense of what level of social standing, income etc. is satisfactory and ensure that any career choice satisfies these conditions I think you can avoid these issues.
The reason I would prefer a satisficing approach for these aspects is, as you pointed out, that optimisation is costly, both in terms of cognitive resources and potentially in terms of happiness. Optimising a career along a number of dimensions is a very complex problem, as you pointed out, particularly when we have incomplete information and struggle to predict our future preferences. Furthermore, continually evaluating whether our career path is 'good enough' on a number of dimensions focusses our mind on the negative aspects of our career rather than being grateful for what we have.
And while it's incredibly important to ensure that you're appropriately tending to your wants/needs other than impact, impact has a broader range than the other factors which makes optimisation more important (one path may be orders of magnitude more impactful than another, but is less likely to differ to such a degree on other dimensions).
This approach might also be worthwhile as much of what these other factors are aiming for is likely to be something like happiness, and satisficing is more likely to be conducive to happiness (https://psycnet.apa.org/record/2002-18731-012).
There's a guy in my (Econ) PhD programme with a working paper relevant to this - I can put you in touch with him if you life: https://arxiv.org/pdf/2203.10305.pdf