Hello Kanu666!
Based on your post it appears you would like to add specific websites as exceptions using Screen Time on your iPad. Is that correct? Screen Time is a great feature to have access to, and I’ll be happy to advise.
There wouldn’t be a way to add an exception for specific websites using Downtime, but you can add websites using Content & Privacy Restrictions and App Limits.
This can be done in Settings > Screen Time > Apple Limits > Add Limit
You can also add web content in Settings > Content & Privacy Restrictions > Content Restrictions > Web Content.
Use Screen Time on your iPhone, iPad, or iPod touch
I would also recommend submitting feedback about the ability to add websites as an exception while using Downtime. Right now this can only be done for specific applications.
Apple Product Feedback
I hope these resources help.
Regards.