Hey AbbasIlahi,
We'd be happy to help out. We understand you're having an issue with flickering when viewing recordings using Cinematic Mode. To clarify, is this flickering occurring during the recording or when viewing after the fact or both? Are you using iMovie to view this content or just the Photos app?
Do you currently have the latest software, iOS 16.3, installed? If not, please update using these steps:
Update your iPhone or iPad wirelessly
1. Back up your device using iCloud or your computer.
2. Plug your device into power and connect to the internet with Wi-Fi.
3. Go to Settings > General, then tap Software Update.
4. If you see more than one software update option available, choose the one that you want to install.

5. Tap Install Now. If you see Download and Install instead, tap it to download the update, enter your passcode, then tap Install Now. If you don't know your passcode, learn what to do.
This is outlined further here: Update your iPhone or iPad - Apple Support
We look forward to gathering more details to begin isolating this matter further.
Take care!