Glass material is smudgy and doesn't look like glass I downloaded this 3D model of a glass vase and I tried fixing the material in Blender using Cycles as my rendering engine but it looks so different in comparison to the material preview. See screenshots below:

Can anyone figure out why this is happening? If anyone can help me out, I'd greatly appreciate it. Been stuck on this for so long already and I'm getting frustrated. I've tried almost everything but nothing seems to work (such as putting roughness to 0, transmission to 1, using glass bdsf, etc)
Some things that could help:

To brighten shadows inside the glass, add more Transmission bounces
For shooting glass (and other shiny objects), use high-contrast lighting
Denoiser still needs a lot of samples to avoid artifacts and smudges


3-4 lights, HDRI environment, 1000 Render Samples + Denoiser


Related:
How to make this glass more realistic?
How to illuminate the darkness inside glass objects in Cycles?