Other ways to hide photos
What people try first
The Hidden album. It's already on the phone, and it's still inside Photos.
Or a locked note, or a folder in Files. Fine for a screenshot. Awkward for video, and you're trusting that app's lock.
Another vault app
Ask two questions. Can the company open your photos? Do the photos leave the phone by default? If either answer is yes, it's a cloud with a passcode.
Mavaul's answers
No, and no. AES-256 on the iPhone, no account. Backups only if you turn them on, encrypted before upload. Free for 20 photos and videos. Privacy is the long version.