I thought they were making a high resolution HUD for the game in the latest patch?

My game still only runs at 1080p at fullscreen. Is there a way to make it 1440p?

I play at 4K and have a sharp UI for the most part.

Make sure your Windows DPI settings don't mess with the resolution. Either set it to 100% via the global display settings, which you probably don't want, or override the default behavior for high DPI scaling in the compatibility settings of the Eastward.exe preferences.