Happiness always reverts back to a baseline level. You will never escape this baseline level.
Up until this point in your life, meaning has been a projection – a goal ahead of you. You have now reached this goal, realised the projection, and must find a new projection, a new project. You must find an I beyond the self, a goal that encompasses but is larger than yourself.
I recommend the book "What is Existentialism?" by Simone de Beauvoir as a starting point.
I've had / am having a similar experience. One of the things I've come to realize -- and I'm not suggesting this is your problem, but it could be -- is that I often compare myself to other people who I gauge as having a level of "success" (a poorly defined term) that I would like to have. I've found that these kinds of comparisons aren't helpful for me, and I haven't really optimized my life around my career anyway. I was (and maybe still am) looking to project the same kind of success for no good reason. In turn, I've learned to really look inward and think about the kinds of things that "recharge my batteries" -- spending time with my family, working on hobbies that provide me a creative outlet, and not setting really high, unreachable expectations for myself. Hope this is helpful.
pet theory of mine, the "wanting self" is a flawed behavior inherited from childhood (that many, myself first, still have), it's useful to stop listening to it. Maybe focus on sharing your time with family, it may lessen the need to satisfy your inner self.
You have no standup meetings, work 4 days a week and only have two calls a week. You are in a good place things can slip into scrum quickly.. you don't want that. Find the things you love about your role and honor them because in a blank you could be at Amazon chasing some dream oncall hoping you were not hired to be fired or trying your own business only to realize you hate selling. Thread carefully.. and start investing in projects outside of work.
Congrats on everything you've achieved!
A great philosopher said "You have made us for yourself, O Lord, and our heart is restless until it rests in you.”
A life without purpose or meaning, even the greatest life, is not enough for the human heart. Our heart was designed for something greater than our jobs, and we only find happiness when we give ourselves entirely to others and to something greater than ourselves.
Maybe St. Augustine wiritings can help you (Confessions is great), and Victor Frenkl's "Man's search for meaning". He was an Auswitch survivor who studied the who survived the most horrific tortures in the Nazi regime. His conclusion was that the ones who survived where the ones that had something to live for.
Hope you find your purpose!
AMGD
It’s never enough because you think external circumstances (your job, your income, your family) are responsible for your happiness - they are not.
Being happy with the way it is has very little to do with your external circumstances and more to do with your internal disposition. That’s why you can find people in all different kinds of circumstances that are happy.
How to get there is a much longer discussion, but focusing on what’s good and feeling grateful for those things is a start.
Hey I'm you but a little younger. I'm writing a book about this called "Enough.".
I think you're spot on with humans always wanting more. More money, more freedom, more relationships, etc.
If you consider a buddhist idea of suffering being the attachment to that idea, you will always be feeling this way. Could you perhaps flip your attachment to become one of detachment where having less fills you up with immense joy and gratitude? What if you looked inward and realized that you are enough and always have been?
Generally speaking, humans seem to want more, better. and different no matter how good we have it. Work is all about activity involving mental or physical effort to achieve a product or goal. It's not called fun, or play or sex. Perhaps if you created your own work, for your own self gratification you may be more fulfilled?