If your iPad screen is too dim or too bright, there are several things you can try to fix it:
Adjust the brightness: Swipe down from the top of the screen to access the Control Center. Here, you can drag the brightness slider to adjust the screen brightness.
Turn off auto-brightness: If your iPad's screen brightness keeps changing, you may want to turn off the auto-brightness feature. Go to Settings > Display & Brightness and toggle off the "Auto-Brightness" option.
Restart your iPad: Sometimes, a simple restart can fix screen issues. Press and hold the power button until the "slide to power off" slider appears. Slide it to turn off your iPad, then press and hold the power button again to turn it back on.
Check for software updates: If your iPad is running an outdated software version, updating it may solve the screen problem. Go to Settings > General > Software Update to check for updates.
Check for hardware issues: If the above steps don't work, it's possible that your iPad has a hardware issue. You may want to take it to an Apple Store or authorized service provider for repair