reflection and refraction are not the same thing. refraction is what you see thru the glass. and this index could be set to 1 if you don’t need this “distortion”. to get more reflectivity out of it you could increase the specular, lower the roughness all the down or increase the metallic value to make it technically like transparent chrome.
There could be different looks based on how you render it. If you use Path Tracing, it has better ray casting which helps with reflection and should make them look better.