Hello Ag_1801,
Welcome to Apple Support Communities.
We understand that when you delete media files permanently that system data increases. We are happy to help.
Please use the steps here to restart your iPhone: Restart your iPhone - Apple Support
- Press and hold either volume button and the side button until the power-off slider appears.
- Drag the slider, then wait 30 seconds for your device to turn off. If your device is frozen or unresponsive, force restart your device.
- To turn your device back on, press and hold the side button (on the right side of your iPhone) until you see the Apple logo.
Please use your computer to see if the storage shows the same using the steps as listed here: How to check the storage on your iPhone and iPad - Apple Support
Use the Finder or iTunes to check the storage on your iOS device
- On a Mac with macOS Catalina 10.15 or later, open the Finder. On a Mac with macOS Mojave 10.14 or earlier, or on a PC, open iTunes.
- Connect your device to your computer.
- Select your device in the Finder or in iTunes. You'll see a bar that shows how much storage your content uses, divided by content type.
- Move your mouse over the bar to see how much storage each content type is using.
If no issue resolution, please contact Apple Support here: Apple Support
Let us know if you have further questions.
Take care.