Is there a way to see all activity on my iPhone 12 Pro Max?

If you find photos you did not take yourself, it sounds like your Apple ID is connected to another device. For example, do you have an iPad lying around available at home or at work?

iCloud Photo is enabled by default, so if another device is signed in to your Apple ID and takes a photo, the photos will sync around all your devices. You can find one of the pictures that you have not taken yourself in Photo app, open it and press the ( i ) button in the bottom line. Then you can see when the picture was taken, which device and possibly the location.

Go to:

Settings -> Apple ID (Your Name)

Scroll down to the bottom. There you can see an overview of the devices that are signed on your Apple ID - if there is one you do not recognize then you must delete it immediately and change your password to your Apple ID.

See here how:

Change your Apple ID password - Apple Support

You can see your activity in Screen Time if you have it enabled.

Go to Settings -> Screen Time

You can also see which apps are using your battery, thus tracking your usage.

Go to: Settings -> Battery

You can also see your physical activity, such as walking, distance, walking speed and more, in the Health App.

Read more here: Use the Health app on your iPhone or iPod touch - Apple Support

Can you not elaborate. I do not quite understand what you want to see with your photos. Please also elaborate on what you associate with incoming activity.