XPS 13 9305 with Intel iris Xe Graphics card cannot run Dell S3221QS monitor at 4K

I have a new Dell XPS 13 9305 purchased December 2021. It has the Intel Iris Xe graphics card.

I am trying to connect to new Dell S3221QS 4K monitor.

I am using a USB-C to display port cable.

I can only achieve HD 1920 x 1080 resolution on the monitor.

I can get 4K resolution easily using my ASUS laptop, so the issue is not with the monitor.

I suspect there is an issue with the XPS 13 or the graphics card. The setting to change the resolution is grayed out and cannot be changed.

The graphics driver is up to date.

The monitor manual (forwarded by dell support) says I might need a graphics adapter.

Thanks to anyone who has any suggestions.

The manual