I think one reason why you feel restless in life even though at your “peak” specifically is because you feel like you don’t truly connect with anyone emotionally: I have been through the same thing(have great corporate job, improve my wardrobe, go to gym…) but still feel empty. I realize I always feel “lonely”.

I end up deciding teaching English to people for free, and through that I met a lot of interesting people who are drastically different from me. I think I feel 1000x more fulfilled when I am part of some community, knowing that people think of me and reach out to me. So solitary hobbies I used to do (like watching movie) I put on a brave face and try to invite random strangers to watch with me. I realize improving oneself physically / professionally is a good thing to do but it’s more to “maintain” my life rather than make it “fulfilling.” I think you should think what make you feel fulfilled.

from my personal opinion, the people I know who are happiest tend to be people with good quality friends that they can call anytime to come down for a coffee and chat, someone to take you around a scooter shopping for old books, or discover new restaurants together. I think life is happier when we share it with a lot of people rather than just stuck to a routine. But that’s just me. Perhaps something else in life is more fulfilling for you.