And this is high poly. I added a subdivision modifier and applied it. You can see that the UV map actually updated as well:
As you can see, the bottom part is horrible. I just want to render it clearly, but you can see that some kind of zig-zag lines in the model.
I adjusted the tolerance and hardness parameters but it doesn't seem to work.
How do I get a clean result when exporting the high-poly version where the subdivision surface modifier has been applied?