On an iPhone 12pro max, wifi calling enabled is or should an icon show this at the top of the screen?

Hi Paulthefloorlayer,

Yes. "If Wi-Fi Calling is available, you’ll see Wi-Fi after your carrier name in the status bar. Then your calls will use Wi-Fi Calling", from: Make a call with Wi-Fi Calling.

This article shows what the icon looks like: Status icons and symbols on your iPhone

Best regards.

"WiFi" and name of your cell service provider will appear (scroll) in the upper left corner of the Wallpaper screen, but not on the Home screen.