Reply To: When viewing a single post page, make the title not a link but just text

If it’s simply a matter of appearance, you can use:

.single .entry-title a {
  color: #777;
  cursor: text;
  font-size: 25px;
  text-decoration: none;
}

https://startupwp.com/topic/customizing-your-theme/

Otherwise, we’ll need to dig into the code to hack the PHP.