Build me a Broken Page Checking Program for a WordPress Website

The website hosts a feed that showcases boats with an image gallery, specs, etc. Some of the pages are no longer considered active when the boat gallery images don't load and the title 'Gallery' no longer appears. The problem pages can be identified by using the word 'Gallery' in the program. The solution is to run a Report generating program periodically that lists all the problem pages and their links so that we can remove them. It should be created and run from the website not the backend.