Full Instagram story not shown on Xs Max 512 GB Gold

Hi,

Quite annoyed here, I finally upgraded from the 6S plus and I am disappointed.

Firstly on Instagram, yeah that community that 1 billion users are present - on my Xs Max Gold 512gb (yeah the expensive one) I don't get the full story display that I did on my 6S?

This picture below is from my Xs Max. Note the black border at the top & bottom of the screenshot.

The shot below is from my 6S. You see the difference, a completely immersive experience.

Is there something wrong with my display settings?

FYI if this is the experience that will remain on the Xs Max, then even though i've used iPhone for 10 years, I am done and will be heading to the S10.

Any body else experienced this?