I dont understand scaling ui resolutions in unity at all?

At first my game looked nice in game view. Now it looks terrible on actual android 1080x 1920. I dont understand why it is the same size in game view, but the font gets blurry, the corners get tiny, the font size or spacing has to be set to ridiculous numbers like 50+. What is the terminology and science behind scaling and resolutions. I have spent all day stuck and baffled. It is the same wxh ratio, why cant it just but the game view onto my android like it is on my PC.

It looks like a anchor problem, you should take a look on the Unity UI tutorial, each UI element has a property called Anchor, this will determin the position and how a UI component will scale when the resolution changes from its original value.