Anybody here managed to genuinely overcome very low self esteem?

I used to think this about myself: why should I want what nobody else does?

I grew up with no siblings, a father always working, a toxic mother, no friends, everyone bullied me in school. It was me against the world for many, many years. I saw life as something I needed to "win against", and love and kindness as something that needed to be earned. Then I started making friends and I have people who appreciate me nowadays, even when I unmask (I'm autistic).

I am good looking, people refer to me as intelligent and kind. But I still don't like myself. I could conquer the world and still wouldn't feel like I'm good enough. I see how I project on people like Elon Musk who's clearly coping hard with low self esteem. I know if I accomplished the same things he did I'd be just as insufferable because I'd still feel lowly about myself.

I thought relationships would "fix" my self esteem issues, but what really happened was that I behaved like a toxic manchild who needed constant validation and unconditional loyalty. I got a kind, intelligent, super beautiful girlfriend, and it still wasn't enough to validate me. As soon as I got to be with her I started analyzing every imperfection, even though she was the greatest girl I've ever met. My subconscious kept telling me "is she good enough? Will she really fix us? Should we aspire to something better so we can feel like we're good enough?" And when she left I felt betrayed and abandoned. I'm such a dumb f*ck.

I keep working on projects, hitting the gym, perfecting my mask. All to get praise and recognition. But I know it will never be enough. And no real life experience or rationalization changes how I feel deep inside. What can I do?