I'm not sure how to "settle and slow down and become happy with the way it is without always wanting more". I've found that for me evolution is a necessary constraint for my happiness. If I'm just doing the same thing over and over and don't feel like I'm progressing towards anything meaningful, then I'm probably bored and unhappy. On the other hand if I'm working towards something I care about, then even if the work is grueling and tedious, I'm happier because I'm making progress towards some purpose.

I'm going to guess you don't derive much fulfillment from your work. There is nothing unique about this. I'd guess that this is the case for most workers, and don't think it has much correlation with pay beyond the minimal amount you need to not be stressed about survival. Maybe a radical view, but I'd even go as far as to say that it is hard for many if not most people to derive any deep sense of fulfillment as a wage laborer (aka. "wagie") reporting to a "boss" because you never have any real equity/ownership or autonomy over your work under such an arrangement. True fulfillment and pleasure in work I believe comes from working purely on your own free will, and not selling your time for a wage.

I was similarly recently working a remote job making good money with great work/life balance and little meetings that at least in the beginning was fulfilling, but at some point the lack of any real ownership over the work and equity made it feel more like clocking in at a factory.

Now I'm unemployed living off savings working on my own project(s) which I've wanted to work on for years, and am way happier with my work than I've been since I can remember (though admittedly am only 1.5 months in so still honeymoon phase). Actually all my happiest work periods in life were all after leaving a job to work on my own projects/interests that I'd been putting off or time constrained due to the day job.

I'm not telling you to quit your job. Just that work fulfillment does not come from money or climbing up the career ladder, it comes from doing things that feel meaningful to you - and chances are that nobody's going to hire you in some traditional job and pay you money to do exactly what you find meaningful unless you're the type who finds the work in traditional jobs meaningful (if this were the case then I imagine you wouldn't have written this post though).

It's easy to tell ourselves we should be happy and grateful because of our six figure salaries and good work-life balance, when in reality many of us have given up and even forgotten about our real passions in life, golden handcuffed so long we forgot those handcuffs are still there. The longer one lives like this, suppressing their true desires in life, the more they forget about their own desires, and become a hollow unhappy shell of who they used to be, filling the void with empty addictions like consumerism and hedonism.

If you feel unfulfilled in work, then find something you're actually genuinely passionate about working on ("my job is technically interesting, and I still learn/improve" is better than nothing, but sounds more like rationalization than real passion). Your motivation should not be making money (or you will burn out), but building something you're passionate about that adds value to the world. Of course monetization matters to make something sustainable, but monetization should not be the primary goal, otherwise you will lose interest and feel unfulfilled because money for money's sake is really not that interesting.