If you're struggling to narrow down your niche because you want to help everyone with everything, I want to share an idea with you that might help.
It's the idea of the door vs. the whole house.
I see your niche as the door that someone comes through. That specific thing that your ideal client avatar is wanting help with...
When someone comes in the door for coaching, your job is to help them with that particular room.
The relationship room
The business room
The health & fitness room
And having a dialed in niche and coaching methodology help you get really good at helping people with that room.
However, it does not mean that you don't get to help your clients with the whole house if you've got the skills.
For example, helping someone find their passion & purpose so they can leave that life sucking job and feel better can also have them looking at their entire life and seeing where they haven't been living passionately or on purpose in other areas. If they haven't been living purposefully in their work, they most likely haven't been living purposefully in their relationships, or with their health, or any other area.
Same goes for something like weight loss. In order for someone to lose weight permanently, there is a LOT of identity shifting that needs to happen. That shift of identity will show up in other areas — guaranteed. That client will begin to feel more confidence, self-esteem, competence, and a whole host of other positive emotions that will bleed into every other area of her life.
So, a niche is just the door they come in and the room you'll focus on, but you can still have a huge impact on the whole house.
With love & joy,

P.S. Is there someone in your life who could benefit from reading this post? Why not share this with them?