Way to make a ui widget component appear flat in FOVs larger than 90 degrees?

Hello!

I have a ui widget component being displayed in front of a camera with a variable and changing FOV greater than 90. I would like the ui widget component to look flat and cover exactly the whole screen regardless of FOV. My thought is that I could use world position offset to distort a high-poly plane containing the ui widget component and make the center of it bulge out toward the camera so it appears flat but my spatial reasoning is failing me here for how exactly to do this to accommodate the changing FOV.

Is my idea possible? Absent of providing a solution, does anyone have any resources as to how I might learn out how to solve this?

Thank you so much!