I have lost the password on parental controls

It seems you have forgot your Screen Time passcode, have you tried clicking forgot passcode?

You may be asked for your Apple ID and password.

For more information: If you forgot your Screen Time passcode - Apple Support

If you still have issues resetting your Screen Time passcode, contact Apple Support.

The only way you will be asked for your Apple ID/Password for a Screen Time reset is if you added it when you set the Screen Time Passcode. When you set the Screen Time Passcode you are given the option to add your Apple ID in case you forget the Passcode. If you skip this step, you are meant with a warning that continuing will not allow you to reset the Passcode. Ignoring this last warning will give you no option to reset the Passcode.

You will then need to Contact Apple directly and it may result in you factory resetting the device. You won't be able to restore from a backup as that will restore the passcode as well. Make sure to save any data, such as pictures, as they would be lost if you are not using iCloud Photos.

Contact Apple for support and service - Apple Support