Frame rate dropping while watching Netflix?

What type of connection are you using, IE. WiFi or cellular?

Try a forced restart.

• Press and quickly release the volume up button

• Press and quickly release the volume down button

• Press and hold the side button.

• When the Apple logo appears, release the button.

https://support.apple.com/en-in/guide/iphone/iph8903c3ee6/ios

I am ruling out any connection issues because you are playing videos from downloaded content (Netflix and Amazon). There should not be any frame drops when watching right from the stored content. You already know this.

Try and Force Restart your iPhone EXACTLY as shown below and see whether that resolves the issue:

• Press and quickly release Volume UP button
• Press and quickly release Volume DOWN button
• Press and Hold the SIDE button until an Apple logo appears and then release the Side button (Can take up to 20 seconds. (DO NOT release Side Button when invited to Slide Power OFF). 

Axel F.

You're welcome, glad to hear you got it resolved.

Kudos to Axel as well, I missed that part about it being downloaded.

Thanks Kurtosis12. You were on the right track.

Axel F.

Keep track of the apps you use before using Netflix, there might an app running that is a resource hog and causing the issue.