If you forgot your screen time password, and you are using macOS Catalina 10.15.4 or iOS 13.4 and later, you can use a new feature to reset your password with an Apple ID.
For earlier macOS, iOS and iPadOS versions, or if you have never set an Apple ID to reset the screen time password, Apple recommends that you wipe and wipe the device, and then set it as a new device to delete the screen time. Unfortunately, according to Apple ’s recommendation, you must set it to a new one.
For iOS 12 users, they can benefit from the '''iPhone Passcode Refixer''' because this tool can help remove screen time passwords without resetting the iPhone and lose all data and settings. You can check this article for more information.
https://www.isumsoft.com/apple/how-to-reset-screen-time-passcode-if-you-forgot-it.html