The flash attack where she jumps up in the air. Not sure about the shorter range flash attack that goes something like dash-flash two or three times.
I started out in immersive mode. I think the yellow/red flashes are the only thing that's always on no matter what mode you choose. I really enjoyed non-combat without the interface, but after a while I needed more info in combat. I turned on the directional attack indicators, and then put most of the rest of the interface onto the touch pad so I could just do a quick swipe to check health, rage, cooldowns, and enemy health. Once I really learned the combat I didn't need it as much except to make the most of my cooldowns. I played Breath of the Wild last year with the minimal interface, and I just recently started Horizon and have had the interface on "dynamic" which lets it fade out after a few moments. It's refreshing to not have all the screen clutter, and makes the exploration parts of these games so much better.