To disable user comments on the site page. Portal owner can easily turn off by Edit the Page. Then scroll to the bottom comments, and turn off the comment. Then Republish your page. Done.
When we need to customise the Quick link box, we need to find what is the Aria-Label value. Right click on the Quick link icon and select "inspect" A list of code will be shown: Find the Aria-label attribute and copy the value. The value of Link D is "Link D.." Note: When you change the icon using image and icon, the format of the value is different. So, do not assume but try to look for the value here. There will not be any error message if you put the wrong label name or code into the Modern Script Editor.