How to Create a "New Identity"?

How to Create a "New Identity"?

I've long understood and concluded that we don't attract what we want, but what we are.

There's a really cool example in my country, Brazil, where a girl pretended to be a millionaire on TikTok and made videos about absurd problems millionaires face (like how she thought it was unfair that her "brother" received a helicopter as a birthday present while her "father" only gave her a Porsche for her birthday).

She went viral. I don't know if she's a millionaire now, but I know her life has changed a lot, and she lives very well financially, is invited to events, and her persona is quite charismatic in a way.

Anyway...

I read a lot, researched a lot, and everything I understood boils down to the phrase: Your Identity is a self-fulfilling prophecy of yourself.

People who followed this path, how did you do it? Did you decide who you would be and nurture that identity/persona? Did you cling to Archetypes and Alter Egos? Did they write down on a sheet of paper who and what they wanted to be? I really need to understand this better.