For years I have been fiddling with the idea of a personal task management system that synchronized status, due dates, prioritization, planning, projects, etc across platforms, and came to a conclusion that nothing beats a flat text file (with own notation for all the above) synchronized well across devices via something reliable yet lightweight like google keep, that I "scan, update, reorder" at least once a day.

One huge insight was a notation to keep track of blocked tasks (usually by other people) and what/whom to "poll" periodically to check the status.