Build me a profile manager project on both web and mobile platforms.

We need a fullstack developer for an application that runs both on web and mobile platforms (ideally built on FLUTTER) the app is a user profile managing page. The user must be able to change some attributes, rent places in a building (eg. squash court), register any visitors to the building, register vehicles into the profile, and add security access conditions. eg. (X door for today/ park A during 4:00pm until tomorrow morning). This must be powered by a back-end consuming data from a PostgreSQL database. The backend is preferred to be coded on python using FLASK.