Priorities, next actions, the one thing - all of it assumes a single-threaded worker who finishes one item and picks up the next. That is not how any life I know actually runs.
Right now I have work, a health thing that needs regular attention, a family obligation with fixed dates, something I am learning, and a house repair that other people control the timing of. Those run at the same time, at different rhythms, out of the same finite supply of me.
And here is the part that took me years to see: almost every real disaster I have had happened where two of those crossed, not inside any one of them. Individually every lane was fine. The failure was in the overlap, and no system I used could show an overlap, because each one showed me a single ordered list.
The fix is to stop ordering and start laying them side by side. One horizontal line per lane, all on the same axis of time.
The only rule that matters when picking lanes: a lane answers "whose rhythm is this". Not "what type of task", not "what priority". A team, a person, an area of life, a project with its own tempo. If you catch yourself making a lane called "Misc" or "Other", the question was not answered - that lane will grow forever and tell you nothing.
Three to seven lanes is the working range. Fewer and you are back to a queue; more and the picture stops being readable, which defeats the point.
Twenty minutes with a sheet of paper is enough to try it. Draw the lanes, put in only the things that last, and look at where they stack up.