I usually use 80% for roughing passes. I use Fusion 360 for CAM, though, so I can tell it to use my finishing bit (at 30-40% stepover) for one final finishing surfacing pass.
I’ve tried the strategy of deeper with lower stepover before, but for most of my projects (shallower carves over a larger area) I get faster results with a depth no greater than the bit diameter and a higher feed rate (with the prior stated 80% stepover). I can’t seem to find settings with deeper cuts where I don’t snap bits.
Yes, it one of the “it depends” variables and governed by stiffness.
With a stiffer system the chip load is more uniform and closer to intended target value.