Thank you for all replies.
Yes, developer and builder are two different roles. From what I researched, developers are the ones who know the list of tasks and do all management of all contractors and work items. Like I mentioned If I do it myself I eventually hire specialized contractors (sub-contractors) to finish each task with high quality. Also as it's a brand new project so there are a constructive list of tasks, not like in other messy projects. And in each step I will always have city inspectors to verify. I also hire a construction inspector to manage the work quality. I act like a manager and I know the tasks to assign to each subs.
I have worked with some general contractors for a big project (not big as this one) and all things they had done were just to hire subcontractors to do the work for them. I feel like the GC get easy money by hiring good sub-contractors to finish the project clean.
I also have a friend who has been a GC for long time and he said the main things of GC is to know all tasks and he said he knows good subcontractors for each tasks and it works just like it.
Anyways thanks to the advices, now I think I would hire a GC or ask a GC for a mentorship.