Welcome GGorn,
Thank you for using Apple Support Communities. Based on your post, you can't restrict the FaceTime app in Screen Time on your daughter's iPhone. We'll do our best to help out.
Could you have FaceTime set up as 'Always Allowed' under Settings > Screen Time > tap your daughter's name at the bottom > Always Allowed? If it's listed at the top, tap the (-) sign to remove it from the list. This will show up under the (+) section, if you wish to ever add it back.
In iOS 14.6, you can also set a limit for this app in Settings > Screen Time > tap your daughter's name > App Limits > Social > FaceTime > Next at the top > then set a time limit that you prefer >make sure 'Block at End of Limit' is checked > then tap 'Add' to save your changes.
If some how this is how you've set it up originally and she's some how bypassing Screen Time, please have a discussion to determine how and Contact Apple Support
Hoping this helps out, take care!