You can hide personal photos and videos on your phone without an app, the method is very easy
Smartphones often contain many private photos and videos that we don't want to share with everyone. So, there's no need to download a separate app. Most Android and iPhone devices already have built-in features that allow you to hide private photos and videos.
How to hide photos and videos on Android phone?
Many Android smartphones offer the option to hide photos and videos within the Gallery or Photos app. Open Gallery and select the photos or videos you want to hide. Tap More or the three-dot option and choose an option like Hide or Move to Secure Folder.
If your phone has a Secure Folder feature, you can store private photos and videos in it. You can also set a separate PIN, password, or biometric lock to unlock it.
Using Locked Folder in Google Photos