This wouldn’t have any effect on a recent macOS version anyways (Apple’s decision). What versions of Scrivener and macOS do you use?
EDIT: “Preferences for disabling insertion point blinking are no longer available on macOS 11 and above. macOS 11 and above do not allow insertion point blinking to be disabled.” https://www.literatureandlatte.com/scrivener/release-notes?os=macOS (For some strange reason I still see those settings, but of course they won’t stop the cursor from blinking.)
Insertion point blinking is controlled at the OS level—modern macOS sadly doesn’t give this option. You can try changing it with some simple Terminal commands to blink very slowly so that it’s virtually unnoticeable. Here’s a tutorial.
Is Typewriter Scrolling is greyed out, your cursor isn’t active where it needs to be for this option to be active. Click into a document to make your cursor active there, and then you can enable Typewriter Scrolling.