The No HUD modifier should still have some sort of reticle to help anchor your perspective. I just completed the GM Savathun's Spire conquest and not having a reticle was very disorienting and somewhat nauseating. I was able to somewhat mitigate the issue by aiming down sights and using the red dot on my gun, but it would be very helpful to still have some semblance of a reticle while hip firing to help reduce motion sickness.