Remote or
Smart controller? I shall assume you meant the
smart controller, the one that has the built in screen. I have the
Smart Controller with my
Mavic 2 Pro.. I bought it later on so it was expensive, they were around $795 new. Mine is the old original
Smart Controller but it does have an HDMI port. Yours may well have one too.
If it does, then you can always buy a larger remote monitor which will plug into your
Smart Controller, assuming you have that HDMI port. The
Smart Controller screen is bright, about 1000Nits, no iPhone will be that bright and even if they tell you, it is, as soon as it begins to get hot, it will begin to dim itself down, so will never stay at its full cold state screen brightness.
I also bought the Feelworld field monitor 729S I think it is and new they cost about $235 but you can find them at less money. This is an amazing 2,200 NITS so is incredibly bright. They now make an even larger monitor which I believe is up to 10 inches and it is touch screen. Do a search for the list of Feelworld monitors but make sure you are looking at the super bright models that have 2,200 NIT screens.
You will be very pleased and thank yourself many times over, that you went with the
Smart Controller (assuming you did) because there is the speed at which you can get flying, over connecting an iphone, plus the simplicity and the fact that you have no cables to lose or damage connection points and only the one battery to keep charged, instead of worry about the standard remote controller battery and the iphone battery to charge.