You have mentioned a lot of things that other people have a hard time overcoming
I wish I could give you a definite answer but there are way too many things inside my head that i can not even find the words to describe what is really the problem there are times where you feel happy and you feel as though everything is enough but there are some times where you still wish something better would happen it is a hard line to be between in on one side you have come to accept reality but on the other side you are wishing for a miracle
Anxiety and existential crises are the huge problem of the century. Trust me, you are not alone and speaking about your thoughts is the best way to find a solution. I know you seems to be a person that do not like to talk about your feelings with others.
No rush, find someone that you trust and try to start talking small things.
Find a therapist and you will discover what is missing for you.
And, if you really dont feel comfortable with that (im that guy too) just start record your feelings, talking your yourself or taking notes about it. Write in a paper, do not do it on the phone.
You are gonna see the difference when you read those things, with a different feeling, in a different state of mind. And thats what gonna help you overcome it.
Stay safe brother and everything you need we are here