If you want to change author name with CSS code in Squarespace, you can use these CSS code to Custom CSS box.
#1. First, click on Author Name to get the author page URL.
In my example, we have:
#2. Use this code to Custom CSS box
a.blog-author-name[href*="5cf999834aa572000105d795"] {
visibility: hidden;
}
a.blog-author-name[href*="5cf999834aa572000105d795"]:before {
visibility: visible;
content: "New author Name";
}
Result:
#3. If you need to disable the Author Name URL, you can add
a.blog-author-name[href*="5cf999834aa572000105d795"] {
visibility: hidden;
pointer-events: none;
}