A family of Microsoft word processing software products for creating web, email, and print documents.
Others are well-being I'm sure but most of what has been suggested affects the pointer, not the cursor. The fact is that the blinking insertion point [i.e., cursor] cannot be altered by Word or by System Settings. Its size is controlled by the OS based on font size & Zoom. The best solution is to work at a higher Zoom percentage than you normally would. Zoom can be controlled by a variety of keyboard methods if you prefer to use them rather than using the mouse/touchpad.
Another option to consider is the use of Dark Mode which allows working in white on a black background and provides higher contrast as illustrated in this screenshot: