screen time passcode

If you don't know the screen time passcode, you will have to erase the iPad and set it up as a new device, not from backup.

Follow the directions in this link --> If you forgot the passcode for your iPhone, iPad, or iPod touch, or your device is disabled - Apple Support

Since you can't restore from backup, you will be able to redownload the apps you own, your photos, emails and text messages as long as they are store in iCloud.

There is no same passcode on every devices unless you make it so.

If you do not remember then you have to restore iPad as new without the backup

using your computer with your iPad connected and selected.