For folks who are struggling to see the controller’s screen, here’s what has worked for us. I purchased one of these 2200nit video monitors from Amazon an I’ve been extremely impressed. It’s about $250 - less than half the price of a DJI Crystal Sky - and it is very clearly visible in blazing direct Florida sunlight.
It can use rechargeable camera batteries, but I mount it on the dashboard and power it off the boat’s batteries. The brightness is equal or better than the Lowrance and Simrad marine GPS displays also installed on the dash.
It’s got an HDMI in and HDMI out port, so you can pass the signal through to a second monitor if needed.
The only downside is that you can’t wear polarized sunglasses when it’s in the landscape orientation. I might experiment with a circular polarizer film over the screen. Does anyone know if that will help?