A manager is not the only person that can provide you accountability. What about users/clients, or partners/co-founders? If you try to ship a super simple pro

A manager is not the only person that can provide you accountability. What about users/clients, or partners/co-founders? If you try to ship a super simple prototype very quickly and get a few users, you would feel accountable to them, and that would give you the motivation to keep building until you make a great service. Alternatively, you could team up with someone. Have a chat every day to share your progress, get some new ideas together, and stay excited about the project.