I just deleted all my iCloud Photos how do I get them back

See the article Delete photos on your iPhone or iPad - Apple Support

Recover deleted photos or videos

1. Open Photos and tap the Albums tab.
2. Tap the Recently Deleted album under Utilities.
3. In iOS 16, iPadOS 16.1, or later, use Face ID or Touch ID to unlock your Recently Deleted album.
4. Tap Select.
5. Select the photo or video that you want to keep and tap Recover. If you want to recover all the photos and videos in the album, tap Recover All.
6. Tap Recover Photo to confirm.

If you accidentally delete a photo or video, you have 30 days to get it back from your Recently Deleted album. When you recover photos and videos, they go back to your Library.