Solopreneur's of IH, how did you build a team and scale?

Hello everyone,

I am a solopreneur, I am looking to build a team but I am stuck mentally. I am a creative person so I love to spend time thinking of various ways how can I scale and innovative things I can do.

I am in email marketing field, where I run client's campaigns on their database via my own infrastructure increasing their revenue.

But since I am alone I have to do the boring grunt stuff myself like handling the infra, database, creating campaigns etc. So I am working with limited clients only and there are many others who want to work with me but I can't take them as clients until I have a team.

Here is what is stopping me:

1. I have no idea how to create a company/business and create a proper system.
2. I am an overthinker so I spend a lot of time thinking "what if my employees run away with my client's database?"
3. I've always worked alone for years so there is some fear on running a business properly.

Does anyone have any books they can recommend where they talk about how to build a proper business and system out of your hobby or any advice which would be helpful for someone like me?
I think my biggest problem is I am thinking too much and I need a decent system which can run things automatically where I can only focus on scaling and hiring top talent.

I am sorry I know this post seems little out of place lol but I hope you understand what I am trying to say.

Thanks!