Puzzle #384 - A Learning Experience (Every Second Straight)

I believe that I've mentioned that I'm making 1 puzzle for every genre that PuzzleDuel has, to submit in bulk and provide quality puzzles for everyone. Well, I recently got to Every Second Straight, a loop genre that I only knew from the site. To make matters worse, I solved all prior examples by intuition and tweaking, and had no idea where to begin logically. I suspect many solvers of my puzzle were in the same boat, though I promise there's a clean path through this puzzle with the right knowledge.

puzz.link interface      penpa interface      PuzzleDuel interface

Solving tips after the break. And by tips, I mostly mean revealing the biggest secret this genre holds.