As others have said, it is not entirely clear what you mean by sharp. Based on the rounded corner and button example you gave previously, I think it might just be the graphic design. MacOS has had a lot of time invested into its design language including subtle things like a thin, almost glass-like specular border around windows and then a drop shadow. This very much becomes a matter of taste in many cases, but for some it helps identify boundaries more precisely.
Perhaps have a look at https://github.com/vinceliuice/WhiteSur-gtk-theme, which replicates MacOS as closely as possible. You may be able to experiment with it side by side and see if you can figure out exactly what design element it is that you are looking for.
As others have said, it is not entirely clear what you mean by sharp. Based on the rounded corner and button example you gave previously, I think it might just be the graphic design. MacOS has had a lot of time invested into its design language including subtle things like a thin, almost glass-like specular border around windows and then a drop shadow. This very much becomes a matter of taste in many cases, but for some it helps identify boundaries more precisely. Perhaps have a look at https://github.com/vinceliuice/WhiteSur-gtk-theme, which replicates MacOS as closely as possible. You may be able to experiment with it side by side and see if you can figure out exactly what design element it is that you are looking for.