Split the project into sub-tasks and order them on a kanban board (Physical/Digital). Figure out which sub-tasks are most important and work through them. Assign them to people if need be. Take time out to do a standups around this board at the start/end of the day to figure out where you're at. Higher ups will be able to see this too and probably will appreciate the clarity.

Even if you don't hit your full deadlines you'll have a more complete 'product' this way