When setting-up the new iPad for your Daughter - and using her own AppleID - the new iPad will have inherited any parental controls previously applied.
A child’s iPad, with controls applied, will not allow the child to sign-out from iCloud; you cannot manage controls from the child’s iPad, but must do so from the Parents account/device. As described, you are now using the iPad that is signed-in to iCloud (and other Apple Services) with your Daughter’s AppleID - and therefore cannot sign-out. You must therefore make any changes to applied controls from a device that is not locked-down by the very restrictions that you are attempting to remove.
You may find this information to be helpful with setting-up/managing the AppleID of a minor:
Apple for Kids - Official Apple Support
Help your child set up an iPhone, iPad, or iPod touch - Apple Support
Family Sharing and Apple ID for your child – Apple Support
Use parental controls on your child's iPhone, iPad and iPod touch – Apple Support
Use Screen Time on your iPhone, iPad or iPod touch – Apple Support
Set up Screen Time for a family member on iPad - Apple Support
When re-purposing an iPad previously used by someone else, including a child, you should fully wipe the iPad - and then set-up again “as new”:
What to do before you sell, give away, or trade in your iPhone, iPad, or iPod touch - Apple Support
