How to get my photos from iCloud to my new device

If your photos are in iCloud Photos, just turn on iCloud Photos in the new device (using the same Apple ID for iCloud) and the photos will sync with it. See: Set up and use iCloud Photos - Apple Support

If you didn't have iCloud Photos turned on in the old device but do have an iCloud Backup, use the backup to set up the new device. See the iCloud section of Transfer data from your previous iOS or iPadOS device to your new iPhone or iPad - Apple Support

You might not have enough cloud storage, like @foxfifth said, try turning on cloud photos if it isn't.