Don't waste your time and energy on trying to become someone else.
Instead give yourself permission to be exactly as you are.
Discussion
Surely it’s okay to have ambitions? Or suppose I’m a spousal abuser or inveterate gambler?
Agree. But both in fulfilling your ambitions and fighting your own demons, you are still working to mold the clay of yourself.
The first step to that anyway is to accept yourself as you are. Only then can you try to get better with this as a reference.
By 'someone else' I meant more trying to become the people you admire, or trying to chase the daydreams that grown up world or social media stuffs into your head.