Photos

Check your Recently Deleted album

1. In iOS 16, iPadOS 16.1, or later, use Face ID or Touch ID to unlock your Recently Deleted album.
2. Tap a photo or video, then tap Recover. To recover multiple photos, tap Select, select your photos or videos, then tap Recover.
3. Confirm that you want to recover the photos or videos.

If you're missing photos or videos in the Photos app

If you are saying that

1. you had 'iCloud Photos' turned on in iCloud Settings, and
2. The photos are missing from iCloud as well as missing from your phone, and
3. They used to be in iCloud

then the only place they can be is in "Recently Deleted" folder in iCloud.com

However it would be difficult for all those photos to be deleted all at once so maybe you had them somewhere else like Google Photos??