How do I delete photos from my iCloud without them deleting on my phone?

You can’t. If you use iCloud Photos, whatever you do on a device or in iCloud.com is reflected on all devices and in iCloud. iCloud is not off device storage. It is a syncing service only.

Set up and use iCloud Photos - Apple Support

Even the photos and videos you delete on one device, delete everywhere that you use iCloud Photos. And if you want to get a photo back, you can restore it from the Recently Deleted album for 30 days.

"You can't...". Rather short sighted don't you think?

Go to Settings>Your Name>iCloud>Manage Storage>Backups>Your Phone Backup>Choose Data to Backup. You can pick and choose what you want to backup to iCloud.

How do I delete photos from my iCloud without them deleting on my iPad?

My iPhone keeps telling me it can't back up because the cloud is full. What is it that wants to back up? I don't need photos backed up, because Google Photos keeps them for me without charging me. How do I take them off the icloud in bunches? What else does my phone need backed up?

Maxfli58 wrote:

"You can't...". Rather short sighted don't you think?

Indeed. I would never use iCloud photos. It makes no sense to me but it is wildly popular with many users.