Question about TV resolution and playing video files

I have a Samsung 4k TV and an Intel NUC. I’m using the HDMI out to the receiver to the TV. So I only get 4k @ 30hz. When I play any of the videos from my iPhone which are 1080p @ 60fps, the TV says it’s still running 4k @ 30hz. I can’t tell if it’s actually running 1080p @ 60fps or not. My TV doesn’t have a great way to always tell you what resolution it’s running in unfortunately, however when I run a regular movie at 24fps, my TV does say it’s running 4k @ 24hz. When I bring up the info panel while playing the movie, it shows the correct fps. I also have Kodi set to adjust playback on start/stop. Am I running the iPhone video at the correct fps?