The way I get around that is that my projects are REVIEW TASKS. I review them two weeks before they are due and every Saturday after that and the day before they are due and then the day after they are due I check the project done.
Every task inside the project then gets reviewed on review day. If a task inside the project needs to get done first it has a due date and it shows up in my Focus.
So basically my Focus list is filled with either a project I need to review or a task I need to do.
This way I never forget a task inside a project that didn’t have a due date