When using PDFViewWPF viewer, the page graphics become blurry as the DPI scale of the OS increases.
This option is available from under Display Settings and Scale and layout where there are options such as 150%. For example, this can change if users happen to be using high DPI monitors.
The option PdfViewWpf.PixelsPerUnitWidth is what you are looking for.
So for 150% you could try 1.5.
You would use something like this to determine the user setting (sadly Microsoft doesn’t seem to make this option is easy to access).