What is he misguided about, and what is the complexity he is simplifying. I ask out of genuine intrigue. Reading the post it comes across as someone who appeared to need to make a change in his life, unsure of what to change. He took a chance on a new role and has found himself happier for it.
OP is mistaking positive feelings (short term, extrinsic) with wellbeing (long term, intrinsic). Their excitement probably allows them to neglect any underlying problems. When the excitement wears off, issues that haven't been addressed are likely to reappear. All of this is purely speculation of course, based on my reading of the post.
Wouldn't "a rewarding career" qualify as long-term, intrinsic wellbeing? Cynics may believe no such thing exists, but I don't think it's a universal view.
Of course, there's always risk that the job changes and becomes worse. In a Series D company, we know that could happen at any time.
> Wouldn't "a rewarding career" qualify as long-term, intrinsic wellbeing?
Depends on what one understand by “rewarding”. If it's compensation, title, status, achievements, etc., these are extrinsic factors. Regardless, I don't see any evidence for a rewarding career in the OP.
I've generally heard "rewarding" in this context used to mean "satisfying and/or meaningful" – e.g, a teacher who loves their job and is able to see their students learn and grow happily would be said to have a rewarding job.
For OP, it sounds like an intrinsically rewarding job would be one that involves autonomy, decision-making, a sense of impact - which it sounds like they now have.