How do boundaries relate to success?

Doing the fear work, something hit me: I fear standing up for myself.

Then I thought, “Oh, if you can’t stand up for yourself, then how can you back yourself, and how can you ever be successful in business and life?”

Not to catastrophize things, but, it seems like a huge can of worms. Where is the best place to start – fear, boundaries or self-worth – or all at once?

Thank you !