In what way did you use gapfill? If you gapfill the top step to the bottom step, the generated part should line up with your stairs perfectly, and can be used to create the railing. This assumes that each individual step is an equal distance away from each other, or some won’t line up with the gapfill.
The definite answer is that the steps and the railing have unparalleled alignment. First of all, the right railing after the first steps does not have an equivalent bottom connector, which is that the bottom of the railing is starting from 1 rather than 0. In other words, unnoticed OBOE.
Second of all, the connecting block is not placed correctly, set slightly off from the edge and it will be fine(clipping into the wood). If you still can’t line it up, duplicate the stairs and simplify by removing the top half and recreating the railing as if it was only straight forward.
Finally, there is nothing wrong with a GapFIll plugin, it works perfectly.
I’ve read all of the posts on how to solve this issue, (and even installed the SBS plugin @fourpapa1 has mentioned. I’ve found them useful, but I’ve figured out a solution for my issue (not that they’re useless, I just came up with a easier way).
Since I know all of the steps are the same height and distance from each other, I made a wedge from the first step as shown:
Then I brought the wedge up to the next step. I brought both wedges higher than their anticipated steps.
I then continued the process until I got to the top of the first half of the staircase.