Re: "Trying to steam movies from my iPhone to a Roku tv"
Am no expert in this area: Seems there are a couple of ways you could stream movies from your phone to the tv.
How to: Use AirPlay to stream video or mirror the screen of your iPhone or iPad - Apple Support
Or
There is a Roku - Official Remote Control on the App Store
Seems you can "Cast media files from your phone, like videos and photos, to your TV"
Use the free Roku mobile app to: Control your Roku devices with a convenient remote;
https://apps.apple.com/us/app/roku-official-remote-control/id482066631