“Airplay” iPhone to iPad….or just control a video?

Looking for software that will allow me to control video apps on my iPad. My rogue echo bike doesn’t have space for a tablet to watch movies for longer rides, but does have a phone holder. I do have a stand that sits of reach for the tablet (but due to the moving arms of air bike have to get off to adjust the iPad).

I watch a lot of YouTube channels and even hitting the dumb skip commercial/ads button requires stopping workout or waiting through a few minutes of ads. Is there a way to “cast” iPhone to iPad, or control the playback of iPad easily.

Have tried a few solutions all of which were very delayed/laggy and audio was several seconds off. There is the accessibility option but didn’t seem to work well for my use case.

Why not just use the phone to play the videos?
Is the storage not enough?

Screen is very small and only can fit vertically on the bike. So 2” wide image vs 12.9……