Video out from Tab S9 to monitor does not fill screen

[JW_Mac]

I'm cable connecting a Galaxy Tab S9 to a 43" Samsung M7 4K UHD monitor and not getting the results I need. As shown here (pic inserted below) the display on the monitor stays about the same size as it was on the tablet.

Portrait mode is required for this (because of the application I am running). Cable connection is required because I will be in a large crowded exhibition hall (terrible cell access) with no wifi available.  I'm using a j5create USB-C to HDMI cable which seems ideal - it supports charging and allows for a longer cord so the tablet can be comfortably held while standing. 

[camb8]

Well go to mirror cast and there's an option u can select to make the screen Resize too fill all of it of the tv screen even though if it's cable or wireless

[JW_Mac]

Thanks camb8, I was optimistic about those Smart View aspect ratio settings working with an HDMI cable.

This setting does address a similar issue with black bars around the display, but much smaller bars. This option is working when in Smart View.  

They don't help the situation I see when I connect the USB-C/HDMI cable. I'm immediately booted out of Smart View when I connect the cable: