Your last sentence has a conflict in it. You are thinking about open-sourcing the project, but you still want to control it? That doesn't sound very open.

Are you at a point where you can launch something? Do you have any feedback from potential users or customers?

Launch before you think it is done. You didn't provide enough details about progress so I will make some assumptions. Scale down your startup to a Minimum Viable Product. Do you have any data that points to this startup generating any income right away to pay off any such debt?