how to open a disabled ipad without losing information or content

You can't. If its disabled the data on it is already gone.

You should have backups made to iTunes or iCloud to prevent this sort of thing.

Your only option is to restore the iPad. If you had a backup made prior to this happening it can be restored onto the iPad to recover the data, Otherwise the iPad will be wiped clean.

If your iPad is disabled, or you have forgotten your iPad passcode, you’ll need to follow this process:

If you’ve forgotten the passcode on your iPad, or your iPad is disabled – Apple Support

You’ll need access to either a PC (with iTunes installed) or a Mac (with iTunes or Finder - as appropriate for the installed version of MacOS). Any locally stored data will be lost, however, you’ll be able to restore your data from your iCloud or iTunes backup at conclusion of the process.

You’ll also need your AppleID and associated password. If these have also been forgotten, they can be recovered here:

https://iforgot.apple.com

To recover your credentials, you’ll need access to one of the following:

• Your primary email address mailbox that corresponds with your AppleID
• Any of the secondary/recovery email addresses that should be configured for your AppleID account
• Any of the trusted telephone numbers (fixed line or Cellular/Mobile) that are associated with your AppleID

Unless you AppleID account has not been fully/correctly configured, or has been seriously neglected, recovery of the AppleID and password should not be difficult.

More information about recovery of your AppleID:

If you forgot your Apple ID - Apple Support

More information about recovery of your AppleID password:

If you forgot your Apple ID password - Apple Support

When you recover access to your credentials, you would be well advised to log-in to your AppleID account from a web browser - and verify/update any email addresses and trusted telephone numbers:

https://appleid.apple.com

iOS and iPadOS are specifically designed so that a disabled device cannot be recovered with intact data. You must erase it to reset it, by design. It is up to owners to keep their backups up to date in order to recover their data.

But a disabled device cannot be reset, by anyone, with intact data. That is designed into iOS and iPadOS purposely.