Hello CH_Regina,
Thanks for reaching out to the Apple Support Communities! We understand you are using Screen Time restrictions to block specific websites from being accessed on your iPad. We are happy to help provide some guidance.
To start, could you let us know if these restrictions have ever worked properly in the past for only allowing some websites? Or has this never worked? Does the same thing happen if you enable the web content restrictions and add a particular website under the "Never Allow" section? We want to further isolate the behavior you are seeing on the iPad. We also want to make sure that the steps outlined in the following article are being followed to enable restrictions. You can read more in the section titled "Prevent web content":
Use parental controls on your child's iPhone, iPad, and iPod touch
We would also recommend making sure that there aren't any software updates available for the iPad. You can check for software updates by going to Settings > General > Software Update.
Keep us updated on how it goes!
Best Regards.