Can't add to Family Sharing after deleting child IDs

Re. greyed-out items, check these possibilities:

● If an app or feature on your device is not working, not appearing, or is restricted (grayed out), a frequent reason is it may have been disabled using Screen Time, or by a technology administrator if you are using a device owned by an employer or educational institution.

- Read this support article If your Apple ID or other options are greyed out in Settings —> If your Apple Account is grayed out in Settings, or you can't sign out - Apple Support

Tap your Settings app > Screen Time > Content & Privacy Restrictions > scroll to Accounts > tap Allow Changes and turn on.

If the issue persists, also try going to Settings > Screen Time and turning off Share Across Devices

- If the device is managed (check: Settings > General > VPN (or Profiles & Device Management), contact the technology department of the organization that is doing the managing.

● Situation where a VPN was preventing action —> Unable to sign out of my Apple ID on my i… - Apple Community

To test for this, remove the VPN entirely, don’t just turn it off.

From another user: "I spoke to Apple support and it can take up to 30 days to delete the child account from the backend." - https://discussions.apple.com/thread/254933351?answerId=259181662022#259181662022