If I use Export Asset, fine details in patterns get smeared and destroyed in the resulting bitmap (png). This happens regardless of whether I scale the object up, or export at super high resolution.

If I use normal Export, the detail is as expected. In fact, this happens even at very low resolutions where you naturally expect to lose detail. Regardless, Illustrator does attempt to preserve brightness and detail as best as possible given the resolution when choosing normal Export. But with Export Asset, the behavior is totally different and, honestly, unusable in most cases.