I added a complication to my watch face and modified the title property. However, when I deploy it to my watch (and even in the preview) that text doesn’t show up. I did select the title and clicked on forward in case it is being hidden behind something else. But that didn’t help.
The icon, text and title of complications is by default fixed like for watch battery the complications only shown icon and the text but title is not shown. You can check for step count shown only text and title and icon is missing, for sunrise and sunset icon and text only shown title is missing.
But if you want to change the complication property such as you want to remove the icon and just want to show the text and title then you can customize it from complications properties.