Dynamic Island not present on iPhone 15 Pro Max

Try this:

Open the music app, start playing something, close the music app.

The currently playing song should move to the dynamic island and show the album art and an audio graph

Other apps may use the Dynamic Island in different ways or not at all.

If there is no Dynamic Island, it is not a 15 pro max...

Does it have a notch instead?

What does it say in settings>general>about>model?

The Dynamic Island is the physical cutout at the top of the screen. When inactive it will look like a black pill shape around the camera.

Are you saying that cutout is not there?

Or are you saying that you can't get an App to use it?

Live activities depends on the app being compatible with that.

Contact the app developer for support.