Q How can I clear photos from my iPad without losing them permanently

On your iPad, disable synchronisation of photos with iCloud:

Settings > [Your Name / AppleID] > iCloud > Photos > iCloud Photos - set to OFF

You can hide the pictures. https://support.apple.com/en-us/HT205891

… recognising that “hiding” images does not clear or remove photos from the iPad.

When “hiding”, no storage space is recovered/released from the device.