current view transition stack on ios was built for static transition between two well know layouts, like portrait to landscape rotation change. i would like live reflow too but i suspect 99% of existing apps aren’t ready to reflow at 120hz when they’ve been written around tween(start layout, end layout) style for decades

UIKit apps can already resize fluidly on Mac Catalyst and iPadOS. I suspect the issue here is more related to the video encoding / streaming used for iPhone Mirroring.