PDF blurry in any PDFKit apps, including Preview, Safari, and 3rd party Skim

It is time to bring this back again. I am now using High Sierra 10.13.6 (17G65)

If you want to open a PDF with any app using PDFKit provided by the system, especially when you connected to an old monitor, it is non-readable blurry. Check the pics below that I cropped from 1680 x 1050 LCD screen.

Imagery PDF in Preview: (the CaCl2 part is an annotation made in Preview)

Imagery PDF in Acrobat:

Normal text PDF in preview:

Normal text PDF in Acrobat:

I think you all can see the difference. The imagery PDF is unreadable.

I've noticed that there are some complaints about such problems before, but the discussions are all closed by now, and the problem is still there. Also, I don't see any complaints mentioning the even worse situation on a low res display.

I am not dreaming about apple PDFKit to render PDF like an expert. But since PDFKit is widely used across the system, especially in Safari, it is legit to request the files to be at least sharp enough to read.

I know Apple doesn't want to render PDF like windows do, with sub-pixel. But I think the text in Safari is crisp enough and I like the rendering style of that. Why it comes so difficult with PDF? Does Apple not do test for older screens anymore?

Thank you all for reading, if you suffer the same, please leave a note!