icloud

If you're missing photos or videos in the Photos app on a mobile device, read this support article --> If you're missing photos or videos in the Photos app - Apple Support

- Check your Recently Deleted folder

- Make sure that iCloud Photos is turned on

- Sign in with the same Apple ID

- Unhide your photos

Have you logged into icloud.com and used the Photos app there to check they are in iCloud?

Make sure photos are set to sync, and that you are using the same Apple ID you were using before. Change which apps sync and store data with iCloud - Apple Support